# Science & Philosophy: Mathematics to Methanal trimer

Science Encyclopedia

## Matriarchy - Nineteenth-century Evolutionary Theory, Twentieth-century Gender And Kinship Studies, Alternatives To Matriarchy: Matrism, Gender Egalitarianism, And Diarchy

Matriarchy is usually defined as a political system in which women are the dominant political actors, as opposed to patriarchy, in which men are the exclusive or primary heads of families, social groups, or political states. But matriarchy has always been a controversial term, since whenever it is mentioned, there are debates about whether matriarchies are imagined utopias or real societies, wheth…

## Matrix

A matrix is a rectangular array of numbers or number-like elements: These rules for adding and subtracting matrices give matrix addition the same properties as ordinary addition and subtraction. It is closed (among matrices of the same size), commutative, and associative. There is an additive identity (the matrix consisting entirely of zeros) and an additive inverse: This latter def…

## Matter

In 1804, the English scientist John Dalton formulated the atomic theory, which set out some fundamental characteristics of matter, and which is still used today. According to this theory, matter is composed of extremely small particles called atoms, which can be neither created nor destroyed. Atoms can, however, attach themselves (bond) to each other in various arrangements to form molecules. A ma…

## Maunder Minimum

The Maunder minimum is the name given to a period of extreme solar inactivity that occurred between 1645 and 1710. Of particular interest is that this period of inactivity corresponds closely to one of the coldest periods of the so-called "Little Ice Age" in Europe, a time of long, cold winters that caused severe hardships in the pre-industrial revolution world. This has led scientis…

## Maxima and Minima - Applications

Finding the maxima and minima, both absolute and relative, of various functions represents an important class of problems solvable by use of differential calculus. The theory behind finding maximum and minimum values of a function is based on the fact that the derivative of a function is equal to the slope of the tangent. When the values of a function increase as the value of the independent varia…

## Mechanical Philosophy - Background, Major Advocates Of The Mechanical Philosophy, Later Developments, Bibliography

The mechanical philosophy was a philosophy of nature, popular in the seventeenth century, that sought to explain all natural phenomena in terms of matter and motion without recourse to any kind of action at a distance (cause and effect without any physical contact). During the sixteenth and seventeenth centuries, many natural philosophers rejected Aristotelianism, which had provided the form of an…

## Median

The median is a measure of central tendency, like an average. It is a way of describing a group of items or characteristics instead of mentioning all of them. If the items are arranged in ascending order of magnitude, the median is the value of the middle item. If there is an odd number of items in the group, the median can be found precisely. For example, assume that 27 test scores are arranged f…

## Medical Genetics

Medical genetics is a multi-dimensional study of medically significant human genetic variation. Molecular diagnostics is the newest specialty field in genetics and allows a better understanding of heredity and disease at the molecular level. Disorders due to mutations as small as a single base change in the DNA can now be explained. Once the mutation is known, clinical laboratory testing can usual…

## Medicine in India - Systematic Medicine, Medical Concepts And Therapies, Surgery, Modernization And Globalization, Bibliography

The systematic doctrines of ayurvedic medicine included a humoral theory somewhat akin to that of Hippocrates and Galen. Indian medicine admitted three humoral substances, namely, wind, bile, and phlegm. However, a certain indecision is visible within the tradition as to the status of blood, which shared with the humors the critical feature of being able to cause illness through becoming corrupt, …

## Eastern Meditation - Bibliography

Many religious traditions have practices that could possibly be labeled meditation. In Judaism, Christianity, and Islam, these practices are usually associated with prayer, contemplation, or recitation of sacred texts. In the religious traditions of the Native Americans, Australian aboriginals, Siberian peoples, and many others, what could be identified as meditation techniques are incorporated wi…

## Meiosis - Meiosis I, Meiosis Ii, Control Of Meiosis, Human Gamete Formation, Mistakes During Meiosis - Events of meiosis

Meiosis, also known as reduction division, consists of two successive cell divisions in diploid cells. The two cell divisions are similar to mitosis, but differ in that the chromosomes are duplicated only once, not twice. The end result of meiosis is four daughter cells, each of them haploid. Since meiosis only occurs in the sex organs (gonads), the daughter cells are the gametes (spermatozoa or o…

## Membrane

Cell membranes or plasma membranes surround cells, separating the cytoplasm and organelles on the inside from the extracellular fluid on the outside. Several cell organelles (mitochondria, endoplasmic reticulum, and Golgi bodies) are also bounded by membranes. The membrane allows a cell or organelle to maintain a constant internal environment, usually one that is quite different from the medium su…

## Meme - The Selfish Meme, Memetic Engineering, Criticism Of Memetic Theory, Bibliography

Meme is indeed an interesting and apt subject to include in a dictionary of the history of ideas, for it is nothing less than a meta-concept for describing the transmission of knowledge among persons and cultures. Memetics—the study of memes—is, briefly stated, evolutionary theory applied to ideas. The word itself was coined by the British biologist Richard Dawkins in his 1976 book T…

## Memory - History, Theories Of Basic Memory Processes, Models Of Memory Operation, Three Information Processing Systems - Divisions of long-yerm memory

Memory refers to the mental systems and processes involved in storing and recalling information about stimuli that are no longer present, as well as to all of the information that is stored. Memory is essential to healthy human functioning, and it can be said that every mental process involves some aspect of memory. Indeed, the ancient Greek philosopher Cicero once described memory as "the …

## Mendelian Genetics

Mendelian genetics is the study of simple patterns of inheritance. Gregor Mendel (1822-1884), an Austrian monk was the first to publish an extensive study of how various traits are passed from parent to progeny. He studied simple garden pea plants, plotting in detail their various physical traits, and studying how combinations of various parental traits produced particular traits in the progeny. F…

## Menstrual Cycle - Proliferative Phase, Secretory Phase, Menstruation

The menstrual cycle technically refers to the cyclic changes that take place in the lining of the human uterus over the course of approximately 28 days in adult females. These cycle changes are associated with cyclic changes in the ovaries and in the brain and ovarian hormones. The term "menstrual" comes from the Latin word menses, meaning month. The purpose of the cyclic changes is …

## Mental Representation - History, Mental Content, The Nature Of Mental Representation, Representational Format, Bibliography

Humans are surrounded by representations. Some of these occur naturally—for example, tree rings and footprints—while others are artificial—for example, words and photographs. Whatever their origins, all share a fundamental feature: they stand for something. Tree rings stand for the age of the tree; footprints stand for the entity that made them; a photograph stands for that wh…

## Mercurous Chloride

Mercurous chloride has been most often used as a treatment for intestinal worms. In the past, large doses were often used to stimulate the intestines and remove blockages, although it is rarely used in medicine today due to the toxicity of mercury. When it is used as a laxative, if the treatment fails to work, large doses of other laxatives and water must be used to insure that no mercury is allow…

## Mercury (Element) - Properties Of Mercury, Toxicity

Mercury is a metallic chemical element identified by the symbol Hg on the periodic table. It is silver in color and, unlike other metals, is liquid at room temperature. The ancient name for mercury was quicksilver, meaning "living" silver. This name reflected mercury's lustrous silver color and its unusually lively behavior: when it is poured onto a smooth surface, it forms be…

## Mesoscopic Systems

The prefix "meso-" means "in between" or "intermediate." Mesoscopic systems are those that are larger than atoms and yet very much smaller than the largescale everyday objects that we can see and touch. They are a thousand to a hundred thousand times smaller than the diameter of a human hair and they range in size from several hundred nanometers or billion…

## Mesozoa

The phylum Mesozoa comprises a small group of parasitic animals that are related to flatworms—a widely dispersed group of free-living and parasitic organisms. Some 50 species have been identified in this phylum to date, all of which are exclusively marine in their lifestyle. Relatively few detailed studies have been conducted on the behavior and life cycles of these species and their taxono…

## Metabolic Disorders - Inborn Metabolic Disorders, Endocrine Metabolic Disorders, Screening And Future Treatment

Metabolic disorders are diseases caused by errors in metabolism. The term "metabolism" refers to the sum of the chemical reactions in the body. Metabolic problems can be traced to numerous metabolic pathways found in cells throughout the body. Metabolic reactions are categorized into two types, anabolic and catabolic. Anabolic reactions construct complex molecules from simple molecul…

## Metabolism

Metabolism refers to the highly integrated network of chemical reactions by which living cells grow and sustain themselves. This network is composed of two major types of pathways: anabolism and catabolism. Anabolism uses energy stored in the form of adenosine triphosphate (ATP) to build larger molecules from smaller molecules. Catabolic reactions degrade larger molecules in order to produce ATP a…

## Metal - Crystallography Of Metals, Survey Of The Periodic Table

A material is called a metal based on the way it reacts to other elements. Metallic elements characteristically form positive ions when their compounds are in solution. Their oxides form hydroxides rather than acids with water. Nearly three-fourths of the elements in each group of the periodic table are metals except for the Group 17 (halogen) and Group 18 (noble gas) elements. Most metals form cr…

## Metal Fatigue

Metal fatigue is the process by which a material is slowly damaged by stresses and strains that are less than those needed to actually break the material apart. For example, a steel wire might be used to suspend weights that are less than the amount needed to cause the wire to break apart (its tensile strength). Over time, however, those weights might slowly cause defects to develop in the steel. …

## Metallurgy - Chemical Or Extractive Metallurgy, Mechanical Working - Physical metallurgy, Metallic coatings

Metallurgy is the science and technology of metals. As indicated in Table 1, the recorded history of metal working goes back over 6,000 years. Chemical or extractive metallurgy is concerned with the extraction of metals from ores and with the refining of metals. Physical metallurgy is concerned with the physical and mechanical properties of metals as affected by composition, mechanical working, an…

## Metamorphic Grade - Metamorphic Rocks And Facies, Types Of Metamorphic Facies - Types of metamorphism

Metamorphic grade is a scale denoting the level of pressure and temperature involved in forming a particular metamorphic rock. The scale is based on the first appearance of particular minerals, known as index minerals. Because each mineral crystallizes within a limited pressure and temperature range, the presence of particular index minerals indicates the relatively specific set of conditions that…

## Metamorphic Rock

Metamorphic rock is rock that has changed from one type of rock into another. The word metamorphic (from Greek) means "of changing form." Metamorphic rock is produced from either igneous rock (rock formed from the cooling and hardening of magma) or sedimentary rock (rock formed from compressed and solidified layers of organic or inorganic matter). Most of Earth's crust is made…

## Metamorphism - Types Of Metamorphism, Current Research In Metamorphism

Metamorphism is the process by which the structure and mineral content of rocks transform in response to changes in temperature, pressure, fluid content (gas or water), or a combination of these. Because the minerals that make up rocks are stable only within certain ranges of temperature and pressure, large changes in these conditions cause minerals to change chemically or to change shape, or both…

## Metamorphosis - General Features, Insects, Hormones, Amphibians

Metamorphosis is the transition in overall body pattern that occurs during the life history of some animals following birth or hatching. Two well-known examples are the development of caterpillars into butterflies and tadpoles into frogs. Metamorphosis is considered an indirect form of development, in that a metamorphic animal passes through morphologically distinct stages before reaching the adul…

## Metaphor - The Classical System, The Middle Ages, The Renaissance, The Enlightenment, Romanticism, The Twentieth Century

The dominant Aristotelian idea of metaphor is not, however, either a balanced opposition or mixture of metaphor's two primary aspects. Of the two, Aristotle chooses to emphasize the formal view—perhaps because it confirms the primacy of reason and cooperates with his systematic and pedagogical motives. The philosophical and cultural consequences of Aristotle's formal emphasis …

## Meteorology

Meteorology is a science that studies the processes and phenomena of the atmosphere. Meteorology is subdivided into many specialty areas including—but not limited to—physical meteorology (dealing with physical aspects of the atmosphere such as rain or cloud formation, or rainbows and mirages), synoptic meteorology (the analysis and forecast of large-scale weather systems), dynamic me…