Datasets:
victcn
/
security-classify-data

Dataset card Data Studio Files
xet
Community
1
text
stringlengths
9
2.4k
Hermitian conjugate of kets. It is common to see the usage formula_96, where the dagger (formula_97) corresponds to the Hermitian conjugate. This is however not correct in a technical sense, since the ket, formula_98, represents a vector in a complex Hilbert-space formula_99, and the bra, formula_100, is a linear functional on vectors in formula_99. In other words, formula_98 is just a vector, while formula_100 is the combination of a vector and an inner product. Operations inside bras and kets. This is done for a fast notation of scaling vectors. For instance, if the vector formula_104 is scaled by formula_105, it may be denoted formula_106. This can be ambiguous since formula_91 is simply a label for a state, and not a mathematical object on which operations can be performed. This usage is more common when denoting vectors as tensor products, where part of the labels are moved outside the designed slot, e.g. formula_108. Linear operators. Linear operators acting on kets. A linear operator is a map that inputs a ket and outputs a ket. (In order to be called "linear", it is required to have certain properties.) In other words, if formula_109 is a linear operator and formula_98 is a ket-vector, then formula_111 is another ket-vector.
In an formula_112-dimensional Hilbert space, we can impose a basis on the space and represent formula_98 in terms of its coordinates as a formula_114 column vector. Using the same basis for formula_109, it is represented by an formula_116 complex matrix. The ket-vector formula_111 can now be computed by matrix multiplication. Linear operators are ubiquitous in the theory of quantum mechanics. For example, observable physical quantities are represented by self-adjoint operators, such as energy or momentum, whereas transformative processes are represented by unitary linear operators such as rotation or the progression of time. Linear operators acting on bras. Operators can also be viewed as acting on bras "from the right hand side". Specifically, if is a linear operator and is a bra, then is another bra defined by the rule formula_118 formula_119 In an -dimensional Hilbert space, can be written as a row vector, and (as in the previous section) is an matrix. Then the bra can be computed by normal matrix multiplication.
If the same state vector appears on both bra and ket side, formula_120 then this expression gives the expectation value, or mean or average value, of the observable represented by operator for the physical system in the state . Outer products. A convenient way to define linear operators on a Hilbert space is given by the outer product: if is a bra and is a ket, the outer product formula_121 denotes the rank-one operator with the rule formula_122 For a finite-dimensional vector space, the outer product can be understood as simple matrix multiplication: formula_123 The outer product is an matrix, as expected for a linear operator. One of the uses of the outer product is to construct projection operators. Given a ket of norm 1, the orthogonal projection onto the subspace spanned by is formula_124 This is an idempotent in the algebra of observables that acts on the Hilbert space. Hermitian conjugate operator. Just as kets and bras can be transformed into each other (making into ), the element from the dual space corresponding to is , where denotes the Hermitian conjugate (or adjoint) of the operator . In other words,
formula_125 If is expressed as an matrix, then is its conjugate transpose. Properties. Bra–ket notation was designed to facilitate the formal manipulation of linear-algebraic expressions. Some of the properties that allow this manipulation are listed herein. In what follows, and denote arbitrary complex numbers, denotes the complex conjugate of , and denote arbitrary linear operators, and these properties are to hold for any choice of bras and kets. Associativity. Given any expression involving complex numbers, bras, kets, inner products, outer products, and/or linear operators (but not addition), written in bra–ket notation, the parenthetical groupings do not matter (i.e., the associative property holds). For example: and so forth. The expressions on the right (with no parentheses whatsoever) are allowed to be written unambiguously "because" of the equalities on the left. Note that the associative property does "not" hold for expressions that include nonlinear operators, such as the antilinear time reversal operator in physics.
Hermitian conjugation. Bra–ket notation makes it particularly easy to compute the Hermitian conjugate (also called "dagger", and denoted ) of expressions. The formal rules are: These rules are sufficient to formally write the Hermitian conjugate of any such expression; some examples are as follows: Composite bras and kets. Two Hilbert spaces and may form a third space by a tensor product. In quantum mechanics, this is used for describing composite systems. If a system is composed of two subsystems described in and respectively, then the Hilbert space of the entire system is the tensor product of the two spaces. (The exception to this is if the subsystems are actually identical particles. In that case, the situation is a little more complicated.) If is a ket in and is a ket in , the tensor product of the two kets is a ket in . This is written in various notations: See quantum entanglement and the EPR paradox for applications of this product. The unit operator. Consider a complete orthonormal system ("basis"),
formula_136 for a Hilbert space , with respect to the norm from an inner product . From basic functional analysis, it is known that any ket formula_137 can also be written as formula_138 with the inner product on the Hilbert space. From the commutativity of kets with (complex) scalars, it follows that formula_139 must be the "identity operator", which sends each vector to itself. This, then, can be inserted in any expression without affecting its value; for example formula_140 where, in the last line, the Einstein summation convention has been used to avoid clutter. In quantum mechanics, it often occurs that little or no information about the inner product of two arbitrary (state) kets is present, while it is still possible to say something about the expansion coefficients and of those vectors with respect to a specific (orthonormalized) basis. In this case, it is particularly useful to insert the unit operator into the bracket one time or more. For more information, see Resolution of the identity, formula_141 where formula_142
Since , plane waves follow, formula_143 In his book (1958), Ch. III.20, Dirac defines the "standard ket" which, up to a normalization, is the translationally invariant momentum eigenstate formula_144 in the momentum representation, i.e., formula_145. Consequently, the corresponding wavefunction is a constant, formula_146, and formula_147 as well as formula_148 Typically, when all matrix elements of an operator such as formula_149 are available, this resolution serves to reconstitute the full operator, formula_150 Notation used by mathematicians. The object physicists are considering when using bra–ket notation is a Hilbert space (a complete inner product space). Let formula_151 be a Hilbert space and a vector in . What physicists would denote by is the vector itself. That is, formula_152 Let be the dual space of . This is the space of linear functionals on . The embedding formula_153 is defined by formula_154, where for every the linear functional formula_155 satisfies for every the functional equation formula_156.
Notational confusion arises when identifying and with and respectively. This is because of literal symbolic substitutions. Let formula_157 and let . This gives formula_158 One ignores the parentheses and removes the double bars. Moreover, mathematicians usually write the dual entity not at the first place, as the physicists do, but at the second one, and they usually use not an asterisk but an overline (which the physicists reserve for averages and the Dirac spinor adjoint) to denote complex conjugate numbers; i.e., for scalar products mathematicians usually write formula_159 whereas physicists would write for the same quantity formula_160
Blue Blue is one of the three primary colours in the RYB colour model (traditional colour theory), as well as in the RGB (additive) colour model. It lies between violet and cyan on the spectrum of visible light. The term "blue" generally describes colours perceived by humans observing light with a dominant wavelength that's between approximately 450 and 495 nanometres. Most blues contain a slight mixture of other colours; azure contains some green, while ultramarine contains some violet. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. An optical effect called the Tyndall effect explains blue eyes. Distant objects appear more blue because of another optical effect called aerial perspective. Blue has been an important colour in art and decoration since ancient times. The semi-precious stone lapis lazuli was used in ancient Egypt for jewellery and ornament and later, in the Renaissance, to make the pigment ultramarine, the most expensive of all pigments. In the eighth century Chinese artists used cobalt blue to colour fine blue and white porcelain. In the Middle Ages, European artists used it in the windows of cathedrals. Europeans wore clothing coloured with the vegetable dye woad until it was replaced by the finer indigo from America. In the 19th century, synthetic blue dyes and pigments gradually replaced organic dyes and mineral pigments. Dark blue became a common colour for military uniforms and later, in the late 20th century, for business suits. Because blue has commonly been associated with harmony, it was chosen as the colour of the flags of the United Nations and the European Union.
In the United States and Europe, blue is the colour that both men and women are most likely to choose as their favourite, with at least one recent survey showing the same across several other countries, including China, Malaysia, and Indonesia. Past surveys in the US and Europe have found that blue is the colour most commonly associated with harmony, confidence, masculinity, knowledge, intelligence, calmness, distance, infinity, the imagination, cold, and sadness. Etymology and linguistics. The modern English word "blue" comes from Middle English or , from the Old French , a word of Germanic origin, related to the Old High German word (meaning 'shimmering, lustrous'). In heraldry, the word "azure" is used for "blue". In Russian, Mongolian, Irish, and some other languages, there is no single word for blue, but rather different words for light blue (Russian: , ) and dark blue (Russian: , ) (see Colour term). Several languages, including Japanese and Lakota Sioux, use the same word to describe blue and green. For example, in Vietnamese, the colour of both tree leaves and the sky is . In Japanese, the word for blue (, ) is often used for colours that English speakers would refer to as green, such as the colour of a traffic signal meaning "go". In Lakota, the word is used for both blue and green, the two colours not being distinguished in older Lakota (for more on this subject, see Blue–green distinction in language).
Linguistic research indicates that languages do not begin by having a word for the colour blue. Colour names often developed individually in natural languages, typically beginning with black and white (or dark and light), and then adding red, and only much later – usually as the last main category of colour accepted in a language – adding the colour blue, probably when blue pigments could be manufactured reliably in the culture using that language. Optics and colour theory. The term "blue" generally describes colours perceived by humans observing light with a dominant wavelength between approximately 450 and 495 nanometres. Blues with a higher frequency and thus a shorter wavelength gradually look more violet, while those with a lower frequency and a longer wavelength gradually appear more green. Purer blues are in the middle of this range, e.g., around 470 nanometres. Isaac Newton included blue as one of the seven colours in his first description of the visible spectrum. He chose seven colours because that was the number of notes in the musical scale, which he believed was related to the optical spectrum. He included indigo, the hue between blue and violet, as one of the separate colours, though today it is usually considered a hue of blue.
In painting and traditional colour theory, blue is one of the three primary colours of pigments (red, yellow, blue), which can be mixed to form a wide gamut of colours. Red and blue mixed together form violet, blue and yellow together form green. Mixing all three primary colours together produces a dark brown. From the Renaissance onward, painters used this system to create their colours (see RYB colour model). The RYB model was used for colour printing by Jacob Christoph Le Blon as early as 1725. Later, printers discovered that more accurate colours could be created by using combinations of cyan, magenta, yellow, and black ink, put onto separate inked plates and then overlaid one at a time onto paper. This method could produce almost all the colours in the spectrum with reasonable accuracy. On the HSV colour wheel, the complement of blue is yellow; that is, a colour corresponding to an equal mixture of red and green light. On a colour wheel based on traditional colour theory (RYB) where blue was considered a primary colour, its complementary colour is considered to be orange (based on the Munsell colour wheel).
LED. In 1993, high-brightness blue LEDs were demonstrated by Shuji Nakamura of Nichia Corporation. In parallel, Isamu Akasaki and Hiroshi Amano of Nagoya University were working on a new development which revolutionized LED lighting. Nakamura was awarded the 2006 Millennium Technology Prize for his invention. Nakamura, Hiroshi Amano and Isamu Akasaki were awarded the Nobel Prize in Physics in 2014 for the invention of an efficient blue LED. Lasers. Lasers emitting in the blue region of the spectrum became widely available to the public in 2010 with the release of inexpensive high-powered 445–447 nm laser diode technology. Previously the blue wavelengths were accessible only through DPSS which are comparatively expensive and inefficient, but still widely used by scientists for applications including optogenetics, Raman spectroscopy, and particle image velocimetry, due to their superior beam quality. Blue gas lasers are also still commonly used for holography, DNA sequencing, optical pumping, among other scientific and medical applications.
Shades and variations. Blue is the colour of light between violet and cyan on the visible spectrum. Hues of blue include indigo and ultramarine, closer to violet; pure blue, without any mixture of other colours; Azure, which is a lighter shade of blue, similar to the colour of the sky; Cyan, which is midway in the spectrum between blue and green, and the other blue-greens such as turquoise, teal, and aquamarine. Blue also varies in shade or tint; darker shades of blue contain black or grey, while lighter tints contain white. Darker shades of blue include ultramarine, cobalt blue, navy blue, and Prussian blue; while lighter tints include sky blue, azure, and Egyptian blue (for a more complete list see the List of colours). As a structural colour. In nature, many blue phenomena arise from structural colouration, the result of interference between reflections from two or more surfaces of thin films, combined with refraction as light enters and exits such films. The geometry then determines that at certain angles, the light reflected from both surfaces interferes constructively, while at other angles, the light interferes destructively. Diverse colours therefore appear despite the absence of colourants.
Colourants. Artificial blues. Egyptian blue, the first artificial pigment, was produced in the third millennium BC in Ancient Egypt. It is produced by heating pulverized sand, copper, and natron. It was used in tomb paintings and funereal objects to protect the dead in their afterlife. Prior to the 1700s, blue colourants for artwork were mainly based on lapis lazuli and the related mineral ultramarine. A breakthrough occurred in 1709 when German druggist and pigment maker Johann Jacob Diesbach discovered Prussian blue. The new blue arose from experiments involving heating dried blood with iron sulphides and was initially called Berliner Blau. By 1710 it was being used by the French painter Antoine Watteau, and later his successor Nicolas Lancret. It became immensely popular for the manufacture of wallpaper, and in the 19th century was widely used by French impressionist painters. Beginning in the 1820s, Prussian blue was imported into Japan through the port of Nagasaki. It was called "bero-ai", or Berlin blue, and it became popular because it did not fade like traditional Japanese blue pigment, "ai-gami", made from the dayflower. Prussian blue was used by both Hokusai, in his wave paintings, and Hiroshige.
In 1799 a French chemist, Louis Jacques Thénard, made a synthetic cobalt blue pigment which became immensely popular with painters. In 1824 the Societé pour l'Encouragement d'Industrie in France offered a prize for the invention of an artificial ultramarine which could rival the natural colour made from lapis lazuli. The prize was won in 1826 by a chemist named Jean Baptiste Guimet, but he refused to reveal the formula of his colour. In 1828, another scientist, Christian Gmelin then a professor of chemistry in Tübingen, found the process and published his formula. This was the beginning of new industry to manufacture artificial ultramarine, which eventually almost completely replaced the natural product. In 1878 German chemists synthesized indigo. This product rapidly replaced natural indigo, wiping out vast farms growing indigo. It is now the blue of blue jeans. As the pace of organic chemistry accelerated, a succession of synthetic blue dyes were discovered including Indanthrone blue, which had even greater resistance to fading during washing or in the sun, and copper phthalocyanine.
Dyes for textiles and food. Woad and true indigo were once used but since the early 1900s, all indigo is synthetic. Produced on an industrial scale, indigo is the blue of blue jeans. Blue dyes are organic compounds, both synthetic and natural. For food, the triarylmethane dye Brilliant blue FCF is used for candies. The search continues for stable, natural blue dyes suitable for the food industry. Various raspberry-flavoured foods are dyed blue. This was done to distinguish strawberry, watermelon and raspberry-flavoured foods. The company ICEE used Blue No. 1 for their blue raspberry ICEEs. Pigments for painting and glass. Blue pigments were once produced from minerals, especially lapis lazuli and its close relative ultramarine. These minerals were crushed, ground into powder, and then mixed with a quick-drying binding agent, such as egg yolk (tempera painting); or with a slow-drying oil, such as linseed oil, for oil painting. Two inorganic but synthetic blue pigments are cerulean blue (primarily cobalt(II) stanate: ) and Prussian blue (milori blue: primarily ). The chromophore in blue glass and glazes is cobalt(II). Diverse cobalt(II) salts such as cobalt carbonate or cobalt(II) aluminate are mixed with the silica prior to firing. The cobalt occupies sites otherwise filled with silicon.
Inks. Methyl blue is the dominant blue pigment in inks used in pens. Blueprinting involves the production of Prussian blue in situ. Inorganic compounds. Certain metal ions characteristically form blue solutions or blue salts. Of some practical importance, cobalt is used to make the deep blue glazes and glasses. It substitutes for silicon or aluminum ions in these materials. Cobalt is the blue chromophore in stained glass windows, such as those in Gothic cathedrals and in Chinese porcelain beginning in the Tang dynasty. Copper(II) (Cu2+) also produces many blue compounds, including the commercial algicide copper(II) sulfate (CuSO4.5H2O). Similarly, vanadyl salts and solutions are often blue, e.g. vanadyl sulfate. In nature. Sky and sea. When sunlight passes through the atmosphere, the blue wavelengths are scattered more widely by the oxygen and nitrogen molecules, and more blue comes to our eyes. This effect is called Rayleigh scattering, after Lord Rayleigh and confirmed by Albert Einstein in 1911. The sea is seen as blue for largely the same reason: the water absorbs the longer wavelengths of red and reflects and scatters the blue, which comes to the eye of the viewer. The deeper the observer goes, the darker the blue becomes. In the open sea, only about 1% of light penetrates to a depth of 200 metres (see underwater and euphotic depth).
The colour of the sea is also affected by the colour of the sky, reflected by particles in the water; and by algae and plant life in the water, which can make it look green; or by sediment, which can make it look brown. The farther away an object is, the more blue it often appears to the eye. For example, mountains in the distance often appear blue. This is the effect of atmospheric perspective; the farther an object is away from the viewer, the less contrast there is between the object and its background colour, which is usually blue. In a painting where different parts of the composition are blue, green and red, the blue will appear to be more distant, and the red closer to the viewer. The cooler a colour is, the more distant it seems. Blue light is scattered more than other wavelengths by the gases in the atmosphere, hence our "blue planet". Minerals. Some of the most desirable gems are blue, including sapphire and tanzanite. Compounds of copper(II) are characteristically blue and so are many copper-containing minerals.
Azurite (, with a deep blue colour, was once employed in medieval years, but it is unstable pigment, losing its colour especially under dry conditions. Lapis lazuli, mined in Afghanistan for more than three thousand years, was used for jewelry and ornaments, and later was crushed and powdered and used as a pigment. The more it was ground, the lighter the blue colour became. Natural ultramarine, made by grinding lapis lazuli into a fine powder, was the finest available blue pigment in the Middle Ages and the Renaissance. It was extremely expensive, and in Italian Renaissance art, it was often reserved for the robes of the Virgin Mary. Plants and fungi. Intense efforts have focused on blue flowers and the possibility that natural blue colourants could be used as food dyes. Commonly, blue colours in plants are anthocyanins: "the largest group of water-soluble pigments found widespread in the plant kingdom". In the few plants that exploit structural colouration, brilliant colours are produced by structures within cells. The most brilliant blue colouration known in any living tissue is found in the marble berries of "Pollia condensata", where a spiral structure of cellulose fibrils scattering blue light. The fruit of quandong ("Santalum acuminatum") can appear blue owing to the same effect.
Animals. Blue-pigmented animals are relatively rare. Examples of which include butterflies of the genus "Nessaea", where blue is created by pterobilin. Other blue pigments of animal origin include phorcabilin, used by other butterflies in "Graphium" and "Papilio" (specifically "P. phorcas" and "P. weiskei"), and sarpedobilin, which is used by "Graphium sarpedon". Blue-pigmented organelles, known as "cyanosomes", exist in the chromatophores of at least two fish species, the mandarin fish and the picturesque dragonet. More commonly, blueness in animals is a structural colouration; an optical interference effect induced by organized nanometre-sized scales or fibres. Examples include the plumage of several birds like the blue jay and indigo bunting, the scales of butterflies like the morpho butterfly, collagen fibres in the skin of some species of monkey and opossum, and the iridophore cells in some fish and frogs. Eyes. Blue eyes do not actually contain any blue pigment. Eye colour is determined by two factors: the pigmentation of the eye's iris and the scattering of light by the turbid medium in the stroma of the iris. In humans, the pigmentation of the iris varies from light brown to black. The appearance of blue, green, and hazel eyes results from the Tyndall scattering of light in the stroma, an optical effect similar to what accounts for the blueness of the sky. The irises of the eyes of people with blue eyes contain less dark melanin than those of people with brown eyes, which means that they absorb less short-wavelength blue light, which is instead reflected out to the viewer. Eye colour also varies depending on the lighting conditions, especially for lighter-coloured eyes.
Blue eyes are most common in Ireland, the Baltic Sea area and Northern Europe, and are also found in Eastern, Central, and Southern Europe. Blue eyes are also found in parts of Western Asia, most notably in Afghanistan, Syria, Iraq, and Iran. In Estonia, 99% of people have blue eyes. In Denmark in 1978, only 8% of the population had brown eyes, though through immigration, today that number is about 11%. In Germany, about 75% have blue eyes. In the United States, as of 2006, 1 out of every 6 people, or 16.6% of the total population, and 22.3% of the white population, have blue eyes, compared with about half of Americans born in 1900, and a third of Americans born in 1950. Blue eyes are becoming less common among American children. In the US, males are 3–5% more likely to have blue eyes than females. History. In the ancient world. As early as the 7th millennium BC, lapis lazuli was mined in the Sar-i Sang mines, in Shortugai, and in other mines in Badakhshan province in northeast Afghanistan. Lapis lazuli artifacts, dated to 7570 BC, have been found at Bhirrana, which is the oldest site of Indus Valley civilisation. Lapis was highly valued by the Indus Valley Civilisation (7570–1900 BC). Lapis beads have been found at Neolithic burials in Mehrgarh, the Caucasus, and as far away as Mauritania. It was used in the funeral mask of Tutankhamun (1341–1323 BC).
A term for Blue was relatively rare in many forms of ancient art and decoration, and even in ancient literature. The Ancient Greek poets described the sea as green, brown or "the colour of wine". The colour is mentioned several times in the Hebrew Bible as 'tekhelet'. Reds, blacks, browns, and ochres are found in cave paintings from the Upper Paleolithic period, but not blue. Blue was also not used for dyeing fabric until long after red, ochre, pink, and purple. This is probably due to the perennial difficulty of making blue dyes and pigments. On the other hand, the rarity of blue pigment made it even more valuable. The earliest known blue dyes were made from plants – woad in Europe, indigo in Asia and Africa, while blue pigments were made from minerals, usually either lapis lazuli or azurite, and required more. Blue glazes posed still another challenge since the early blue dyes and pigments were not thermally robust. In , the blue glaze Egyptian blue was introduced for ceramics, as well as many other objects. The Greeks imported indigo dye from India, calling it indikon, and they painted with Egyptian blue. Blue was not one of the four primary colours for Greek painting described by Pliny the Elder (red, yellow, black, and white). For the Romans, blue was the colour of mourning, as well as the colour of barbarians. The Celts and Germans reportedly dyed their faces blue to frighten their enemies, and tinted their hair blue when they grew old. The Romans made extensive use of indigo and Egyptian blue pigment, as evidenced, in part, by frescos in Pompeii.
The Romans had many words for varieties of blue, including , , , , , , , and , but two words, both of foreign origin, became the most enduring; , from the Germanic word "blau", which eventually became "bleu" or blue; and , from the Arabic word , which became azure. Blue was widely used in the decoration of churches in the Byzantine Empire. By contrast, in the Islamic world, blue was of secondary to green, believed to be the favourite colour of the Prophet Mohammed. At certain times in Moorish Spain and other parts of the Islamic world, blue was the colour worn by Christians and Jews, because only Muslims were allowed to wear white and green. In the Middle Ages. In the art and life of Europe during the early Middle Ages, blue played a minor role. This changed dramatically between 1130 and 1140 in Paris, when the Abbe Suger rebuilt the Saint Denis Basilica. Suger considered that light was the visible manifestation of the Holy Spirit. He installed stained glass windows coloured with cobalt, which, combined with the light from the red glass, filled the church with a bluish violet light. The church became the marvel of the Christian world, and the colour became known as the . In the years that followed even more elegant blue stained glass windows were installed in other churches, including at Chartres Cathedral and Sainte-Chapelle in Paris.
In the 12th century the Roman Catholic Church dictated that painters in Italy (and the rest of Europe consequently) to paint the Virgin Mary with blue, which became associated with holiness, humility and virtue. In medieval paintings, blue was used to attract the attention of the viewer to the Virgin Mary. Paintings of the mythical King Arthur began to show him dressed in blue. The coat of arms of the kings of France became an azure or light blue shield, sprinkled with golden fleur-de-lis or lilies. Blue had come from obscurity to become the royal colour. Renaissance through 18th century. Blue came into wider use beginning in the Renaissance, when artists began to paint the world with perspective, depth, shadows, and light from a single source. In Renaissance paintings, artists tried to create harmonies between blue and red, lightening the blue with lead white paint and adding shadows and highlights. Raphael was a master of this technique, carefully balancing the reds and the blues so no one colour dominated the picture.
Ultramarine was the most prestigious blue of the Renaissance, being more expensive than gold. Wealthy art patrons commissioned works with the most expensive blues possible. In 1616 Richard Sackville commissioned a portrait of himself by Isaac Oliver with three different blues, including ultramarine pigment for his stockings. An industry for the manufacture of fine blue and white pottery began in the 14th century in Jingdezhen, China, using white Chinese porcelain decorated with patterns of cobalt blue, imported from Persia. It was first made for the family of the Emperor of China, then was exported around the world, with designs for export adapted to European subjects and tastes. The Chinese blue style was also adapted by Dutch craftsmen in Delft and English craftsmen in Staffordshire in the 17th-18th centuries. in the 18th century, blue and white porcelains were produced by Josiah Wedgwood and other British craftsmen. 19th-20th century. The early 19th century saw the ancestor of the modern blue business suit, created by Beau Brummel (1776–1840), who set fashion at the London Court. It also saw the invention of blue jeans, a highly popular form of workers's costume, invented in 1853 by Jacob W. Davis who used metal rivets to strengthen blue denim work clothing in the California gold fields. The invention was funded by San Francisco entrepreneur Levi Strauss, and spread around the world.
Recognizing the emotional power of blue, many artists made it the central element of paintings in the 19th and 20th centuries. They included Pablo Picasso, Pavel Kuznetsov and the Blue Rose art group, and Kandinsky and Der Blaue Reiter (The Blue Rider) school. Henri Matisse expressed deep emotions with blue, "A certain blue penetrates your soul." In the second half of the 20th century, painters of the abstract expressionist movement use blues to inspire ideas and emotions. Painter Mark Rothko observed that colour was "only an instrument;" his interest was "in expressing human emotions tragedy, ecstasy, doom, and so on". In society and culture. Uniforms. In the 17th century. The Prince-Elector of Brandenburg, Frederick William I of Prussia, chose Prussian blue as the new colour of Prussian military uniforms, because it was made with Woad, a local crop, rather than Indigo, which was produced by the colonies of Brandenburg's rival, England. It was worn by the German army until World War I, with the exception of the soldiers of Bavaria, who wore sky-blue.
In 1748, the Royal Navy adopted a dark shade of blue for the uniform of officers. It was first known as marine blue, now known as navy blue. The militia organized by George Washington selected blue and buff, the colours of the British Whig Party. Blue continued to be the colour of the field uniform of the US Army until 1902, and is still the colour of the dress uniform. In the 19th century, police in the United Kingdom, including the Metropolitan Police and the City of London Police also adopted a navy blue uniform. Similar traditions were embraced in France and Austria. It was also adopted at about the same time for the uniforms of the officers of the New York City Police Department. Gender. Blue is used to represent males. Beginning as a trend the mid-19th century and applying primarily to clothing, gendered associations with blue became more widespread from the 1950s. The colour became associated with males after World War II. Sports. In sports, blue is widely represented in uniforms in part because the majority of national teams wear the colours of their national flag. For example, the national men's football team of France are known as "Les Bleus" (the Blues). Similarly, Argentina, Italy, and Uruguay wear blue shirts. The Asian Football Confederation and the Oceania Football Confederation use blue text on their logos. Blue is well represented in baseball (Blue Jays), basketball, and American football, and Ice hockey. The Indian national cricket team wears blue uniform during One day international matches, as such the team is also referred to as "Men in Blue".
Politics. Unlike red or green, blue was not strongly associated with any particular country, religion or political movement. As the colour of harmony, it was chosen as the colour for the flags of the United Nations, the European Union, and NATO. In politics, blue is often used as the colour of conservative parties, contrasting with the red associated with left-wing parties. Some conservative parties that use the colour blue include the Conservative Party (UK), Conservative Party of Canada, Liberal Party of Australia, Liberal Party of Brazil, and Likud of Israel. However, in some countries, blue is not associated main conservative party. In the United States, the liberal Democratic Party is associated with blue, while the conservative Republican Party is associated with red. US states which have been won by the Democratic Party in four consecutive presidential elections are termed "blue states", while those that have been won by the Republican Party are termed "red states". South Korea also uses this colour model, with the Democratic Party on the left using blue and the People Power Party on the right using red.
Blind Willie McTell Blind Willie McTell (born William Samuel McTier; May 5, 1898 – August 19, 1959) was an American Piedmont blues and ragtime singer, songwriter and guitarist. He played in a fluid, syncopated finger picking guitar style common among many East Coast, Piedmont blues players. Like his Atlanta contemporaries, he came to use twelve-string guitars exclusively. McTell was also adept at slide guitar, unusual among ragtime bluesmen. He sang in a smooth and often laid-back tenor which differed greatly from the harsher voices of many Delta bluesmen such as Charley Patton. He performed in various musical styles including blues, ragtime, religious music, and hokum and recorded more than 120 titles during fourteen recording sessions.
Biography. Most sources give the date of his birth as 1898 but researchers Bob Eagle and Eric LeBlanc suggest 1903 on the basis of his entry in the 1910 census. McTell was born blind in one eye and lost his remaining vision by late childhood. He attended schools for the blind in Georgia, New York and Michigan and showed proficiency in music from an early age, learning to read and write music in braille, first playing the harmonica and accordion and turning to the six-string guitar in his early teens. His family was rich in music; both of his parents and an uncle played the guitar and he and bluesman and gospel pioneer Thomas A. Dorsey were cousins. McTell's father left the family when Willie was young. After his mother died, in the 1920s, he left his hometown and became an itinerant songster. Like Lead Belly, another songster who began his career on the streets, McTell favored the twelve-string guitar whose greater volume made it suitable for outdoor playing. In the years before World War II, McTell traveled and performed widely, recording for several labels under different names: Blind Willie McTell for Victor and Decca, Blind Sammie for Columbia, Georgia Bill for Okeh, Hot Shot Willie for Victor, Blind Willie for Vocalion and Bluebird, Barrelhouse Sammie for Atlantic, and Pig & Whistle Red for Regal Records. The name "Pig & Whistle" was a reference to a chain of barbecue restaurants in Atlanta; McTell often played for tips in the parking lot of a Pig 'n Whistle restaurant. He also played behind a nearby building that later became Ray Lee's Blue Lantern Lounge.
McTell married Ruth Kate Williams, now better known as Kate McTell, in 1934. She accompanied him on stage and on several recordings before becoming a nurse in 1939. For most of their marriage, from 1942 until his death, they lived apart, she in Fort Gordon, near Augusta, and he working around Atlanta. In 1940, John Lomax, a Classics professor at the University of Texas at Austin and his wife, Ruby Terrill Lomax, interviewed and recorded McTell for the Archive of American Folk Song of the Library of Congress in a two-hour session held in their hotel room in Atlanta. These recordings captured McTell's distinctive musical style which bridges the gap between the country blues of the early part of the 20th century and the more conventionally melodious, ragtime-influenced East Coast, Piedmont blues sound. The Lomaxes also elicited from him traditional songs (such as "The Boll Weevil" and "John Henry") and spirituals (such as "Amazing Grace"), which were not part of his usual repertoire. In the interview, John Lomax is heard asking if McTell knows any "complaining" songs (an earlier term for protest songs), to which he replies somewhat uncomfortably and evasively that he does not. The Library of Congress paid McTell $10, the equivalent of $154.56 in 2011, for this two-hour session. The material from this 1940 session was issued in 1960 as an LP and later as a CD under the somewhat misleading title "The Complete Library of Congress Recordings" notwithstanding the fact that it omitted some of Lomax's interactions showing kindness to him and entirely omitting the contributions of Ruby Terrill Lomax.
Ahmet Ertegun visited Atlanta in 1949 in search of blues artists for this new Atlantic Records label and after finding McTell playing on the street, arranged a recording session. Some of the songs were released on 78 rpm discs but sold poorly. The complete session was released in 1972 as "Atlanta Twelve-String". McTell recorded for Regal Records in 1949 but these recordings also met with less commercial success than his previous works. He continued to perform around Atlanta but his career was cut short by ill health, mostly due to diabetes and alcoholism. In 1956, an Atlanta record store owner, Edward Rhodes, discovered McTell playing in the street for quarters and enticed him into his store with a bottle of bourbon where he captured 13 songs on a tape recorder which Prestige Records/Bluesville Records posthumously released as his "Last Session". From 1957 to 1959, McTell was a preacher at Mt. Zion Baptist Church in Atlanta. Blind Willie McTell died of a stroke in Milledgeville, Georgia, in 1959, at the age of 61. He was buried at Jones Grove Church, near Thomson, Georgia, his birthplace. Author David Fulmer, who in 1992 was working on "Blind Willie's Blues", a documentary about McTell, arranged to have a blue marble gravestone erected on his resting place. McTell was inducted into the Blues Foundation's Blues Hall of Fame in 1981 and the Georgia Music Hall of Fame in 1990.
Influence. McTell's influence extended over a wide variety of artists. His most famous song, "Statesboro Blues" was adapted by Taj Mahal with Jesse Ed Davis on slide guitar, then covered and frequently performed by the Allman Brothers Band. It also shows up on Canned Heat's "Goin' Up the Country" album. A short list of some of the artists who have performed the song includes David Bromberg, Dave Van Ronk, The Devil Makes Three, Chris Smither and Ralph McTell, who changed his name because he liked the song. Ry Cooder covered McTell's "Married Man's a Fool" on his 1973 album, "Paradise and Lunch". Jack White, of the White Stripes, considers McTell an influence; the White Stripes album "De Stijl" (2000) is dedicated to him and features a cover of his song "Southern Can Is Mine". The White Stripes also covered McTell's "Lord, Send Me an Angel", releasing it as a single in 2000. In 2013, Jack White's Third Man Records teamed up with Document Records to issue "The Complete Recorded Works in Chronological Order of Charley Patton, Blind Willie McTell and the Mississippi Sheiks".
Bob Dylan paid tribute to McTell on at least four occasions. In his 1965 song "Highway 61 Revisited", the second verse begins, "Georgia Sam, he had a bloody nose", an allusion to one of McTell's many recording names (Note: there is no evidence that he used this name on any recordings). Dylan's song "Blind Willie McTell" was recorded in 1983 and released in 1991 on "The Bootleg Series Volumes 1-3". Dylan also recorded covers of McTell's "Broke Down Engine" and "Delia" on his 1993 album, "World Gone Wrong"; Dylan's song "Po' Boy", on the album "Love and Theft" (2001), contains the lyric "had to go to Florida dodging them Georgia laws", which comes from McTell's "Kill It Kid". The Bath-based band Kill It Kid is named after the song of the same title. A billiards bar and concert venue in Statesboro, Georgia, was named Blind Willie's in the 1990s. The venue is now closed but remains a fond memory for Georgia Southern University students at the time. Another Blind Willie's bar in the Virginia-Highlands neighborhood of Atlanta named after McTell that features blues musicians and bands. The Blind Willie McTell Blues Festival is held annually in Thomson, Georgia.
In 1996, the novelist and former music journalist David Fulmer released "Blind Willie's Blues", a 53-minute documentary about McTell’s life, times, and music, with interviews with African-American history professor Daphne Duval Harrison, blues musician Taj Mahal, guitarist Stefan Grossman, Atlantic Records founder Ahmet Ertegun, McTell's former brother-in-law Rev. A.J. Williams, and Edward Rhodes, who produced McTell's "Last Sessions" recording. In late 2023, the film was remastered by the Southeastern Folklife Collection at Valdosta State University and is currently streaming on YouTube.
BDSM BDSM is a variety of often erotic practices or roleplaying involving bondage, discipline, dominance and submission, sadomasochism, and other related interpersonal dynamics. Given the wide range of practices, some of which may be engaged in by people who do not consider themselves to be practising BDSM, inclusion in the BDSM community or subculture often is said to depend on self-identification and shared experience. The initialism "BDSM" is first recorded in a Usenet post from 1991, and is interpreted as a combination of the abbreviations B/D (Bondage and Discipline), D/s (Dominance and submission), and S/M (Sadism and Masochism). "BDSM" is used as a catch-all phrase covering a wide range of activities, forms of interpersonal relationships, and distinct subcultures. BDSM communities generally welcome anyone with a non-normative streak who identifies with the community; this may include cross-dressers, body modification enthusiasts, animal roleplayers, rubber fetishists, and others. Activities and relationships in BDSM are typically characterized by the participants' taking on roles that are complementary and involve inequality of power; thus, the idea of informed consent of both the partners is essential. The terms "submissive" and "dominant" are usually used to distinguish these roles: the dominant partner ("dom") takes psychological control over the submissive ("sub"). The terms "top" and "bottom" are also used; the top is the instigator of an action while the bottom is the receiver of the action. The two sets of terms are subtly different: for example, someone may choose to act as bottom to another person, for example, by being whipped, purely recreationally, without any implication of being psychologically dominated, and submissives may be ordered to massage their dominant partners. Although the bottom carries out the action and the top receives it, they have not necessarily switched roles.
The abbreviations "sub" and "dom" are frequently used instead of "submissive" and "dominant". Sometimes the female-specific terms "mistress", "domme", and "dominatrix" are used to describe a dominant woman, instead of the sometimes gender-neutral term "dom". Individuals who change between top/dominant and bottom/submissive roles—whether from relationship to relationship or within a given relationship—are called "switches". The precise definition of roles and self-identification is a common subject of debate among BDSM participants. Fundamentals. "BDSM" is an umbrella term for certain kinds of erotic behaviour between consenting adults, encompassing various subcultures. Terms for roles vary widely among the subcultures. "Top" and "dominant" are widely used for those partner(s) in the relationship or activity who are, respectively, the physically active or controlling participants. "Bottom" and "submissive" are widely used for those partner(s) in the relationship or activity who are, respectively, the physically receptive or controlled participants. The interaction between tops and bottoms—where physical or mental control of the bottom is surrendered to the top—is sometimes known as "power exchange", whether in the context of an encounter or a relationship.
BDSM actions can often take place during a specific period of time agreed to by both parties, referred to as "play", a "scene", or a "session". Participants usually derive pleasure from this, even though many of the practices—such as inflicting pain or humiliation or being restrained—would be unpleasant under other circumstances. Explicit sexual activity, such as sexual penetration, may occur within a session, but is not essential. For legal reasons, such explicit sexual interaction is seen only rarely in public play spaces and is sometimes banned by the rules of a party or playspace. Whether it is a public "playspace"—ranging from a party at an established community dungeon to a hosted play "zone" at a nightclub or social event—the parameters of allowance can vary. Some have a policy of panties/nipple sticker for women (underwear for men) and some allow full nudity with explicit sexual acts. The fundamental principles for the exercise of BDSM require that it be performed with the informed consent of all parties. Since the 1980s, many practitioners and organizations have adopted the motto (originally from the statement of purpose of GMSMA—a gay SM activist organization) "safe, sane and consensual" ("SSC"), which means that everything is based on safe activities, that all participants are of sufficiently sound mind to consent, and that all participants do consent. Mutual consent makes a clear legal and ethical distinction between BDSM and such crimes as sexual assault and domestic violence.
Some BDSM practitioners prefer a code of behaviour that differs from SSC. Described as "risk-aware consensual kink" (RACK), this code shows a preference for a style in which the "individual" responsibility of the involved parties is emphasized more strongly, with each participant being responsible for their own well-being. Advocates of RACK argue that SSC can hamper discussion of risk because no activity is truly "safe", and that discussion of even low-risk possibilities is necessary for truly informed consent. They further argue that setting a discrete line between "safe" and "not-safe" activities ideologically denies consenting adults the right to evaluate risks versus rewards for themselves; that some adults will be drawn to certain activities regardless of the risk; and that BDSM play—particularly higher-risk play or edgeplay—should be treated with the same regard as extreme sports, with both respect and the demand that practitioners educate themselves and practice the higher-risk activities to decrease risk. RACK may be seen as focusing primarily upon awareness and informed consent, rather than accepted safe practices.
Consent is the most important criterion. The consent and compliance for a sadomasochistic situation can be granted only by people who can judge the potential results. For their consent, they must have relevant information (the extent to which the scene will go, potential risks, if a safeword will be used, what that is, and so on) at hand and the necessary mental capacity to judge. The resulting consent and understanding is occasionally summarized in a written "contract", which is an agreement of what can and cannot take place. BDSM play is usually structured such that it is possible for the consenting partner to withdraw their consent at any point during a scene; for example, by using a safeword that was agreed on in advance. Use of the agreed safeword (or occasionally a "safe symbol" such as dropping a ball or ringing a bell, especially when speech is restricted) is seen by some as an explicit withdrawal of consent. Failure to honor a safeword is considered serious misconduct and could constitute a crime, depending on the relevant law, since the bottom or top has explicitly revoked their consent to any actions that follow the use of the safeword. For other scenes, particularly in established relationships, a safeword may be agreed to signify a warning ("this is getting too intense") rather than explicit withdrawal of consent; and a few choose not to use a safeword at all.
Terminology and subtypes. The initialism "BDSM" appeared for the first time in 1983 in the scientific paper "S and M: Studies in Dominance and Submission" by Thomas Weinberg. It was later popularized in a list of frequent questions for the site alt.sex.bondageFAQ and reposted between 1995 and 1997 in the forum soc.subculture.bondage-bdsm. It stands for: These terms replaced "sadomasochism", as they more broadly cover BDSM activities and focus on the submissive roles instead of psychological pain. The model is only an attempt at phenomenological differentiation. Individual tastes and preferences in the area of human sexuality may overlap among these areas. Under the initialism BDSM, these psychological and physiological facets are also included: The term "bondage" describes the practice of physical restraint. Bondage is usually, but not always, a sexual practice. While bondage is a very popular variation within the larger field of BDSM, it is nevertheless sometimes differentiated from the rest of this field. A 2015 study of over 1,000 Canadians showed that about half of all men held fantasies of bondage, and almost half of all women did as well. In a strict sense, bondage means binding the partner by tying their appendages together; for example, by the use of handcuffs or ropes, or by lashing their arms to an object. Bondage can also be achieved by spreading the appendages and fastening them with chains or ropes to a St. Andrew's cross or spreader bars.
The term "discipline" describes the use of rules and punishment to control overt behaviour. Punishment can be pain caused physically (such as caning), humiliation caused psychologically (such as a public flagellation) or loss of freedom caused physically (for example, chaining the submissive partner to the foot of a bed). Another aspect is the structured training of the bottom. Dominance and submission (also known as "D&s", "Ds" or "D/s") is a set of behaviours, customs and rituals relating to the giving and accepting of control of one individual over another in an erotic or lifestyle context. It explores the more mental aspect of BDSM. This is also the case in many relationships not considering themselves as sadomasochistic; it is considered to be a part of BDSM if it is practiced purposefully. The range of its individual characteristics is thereby wide. Often, BDSM contracts are set out in writing to record the formal consent of the parties to the power exchange, stating their common vision of the relationship dynamic. The purpose of this kind of agreement is primarily to encourage discussion and negotiation in advance and then to document that understanding for the benefit of all parties. Such documents have not been recognized as being legally binding, nor are they intended to be. These agreements are binding in the sense that the parties have the expectation that the negotiated rules will be followed. Often other friends and community members may witness the signing of such a document in a ceremony, and so parties violating their agreement can result in loss of face, respect or status with their friends in the community.
In general, as compared to conventional relationships, BDSM participants go to greater lengths to negotiate the important aspects of their relationships in advance, and to contribute significant effort toward learning about and following safe practices. In D/s, the dominant is the top and the submissive is the bottom. In S/M, the sadist is usually the top and the masochist the bottom, but these roles are frequently more complicated or jumbled (as in the case of being dominant, masochists who may arrange for their submissive to carry out S/M activities on them). As in B/D, the declaration of the top/bottom may be required, though sadomasochists may also play without any power exchange at all, with both partners equally in control of the play. Etymology. The term "sadomasochism" is derived from the words "sadism" and "masochism". These terms differ somewhat from the same terms used in psychology since those require that the sadism or masochism cause significant distress or involve non-consenting partners. "Sadomasochism" refers to the aspects of BDSM surrounding the exchange of physical or emotional pain. Sadism describes sexual pleasure derived by inflicting pain, degradation, humiliation on another person or causing another person to suffer. On the other hand, the masochist enjoys being hurt, humiliated, or suffering within the consensual scenario. Sadomasochistic scenes sometimes reach a level that appears more extreme or cruel than other forms of BDSM—for example, when a masochist is brought to tears or is severely bruised—and is occasionally unwelcome at BDSM events or parties. Sadomasochism does not imply enjoyment through causing or receiving pain in other situations (for example, accidental injury, medical procedures).
The terms "sadism" and "masochism" are derived from the names of the Marquis de Sade and Leopold von Sacher-Masoch, based on the content of the authors' works. Although the names of de Sade and Sacher-Masoch are attached to the terms sadism and masochism respectively, the scenes described in de Sade's works do not meet modern BDSM standards of informed consent. BDSM is solely based on consensual activities, and based on its system and laws. The concepts presented by de Sade are not in accordance with the BDSM culture, even though they are sadistic in nature. In 1843, the Ruthenian physician Heinrich Kaan published ' ("Psychopathy of Sex"), a writing in which he converts the sin conceptions of Christianity into medical diagnoses. With his work, the originally theological terms "perversion", "aberration" and "deviation" became part of the scientific terminology for the first time. The German psychiatrist Richard von Krafft-Ebing introduced the terms "sadism" and "masochism" to the medical community in his work ' ("New research in the area of Psychopathy of Sex") in 1890.
In 1905, Sigmund Freud described sadism and masochism in his "Three Essays on the Theory of Sexuality" as diseases developing from an incorrect development of the child psyche and laid the groundwork for the scientific perspective on the subject in the following decades. This led to the first time use of the compound term "sado-masochism" (German ") by the Viennese psychoanalytic Isidor Isaak Sadger in their work, " ("Regarding the sadomasochistic complex") in 1913. In the later 20th century, BDSM activists have protested against these conceptual models, as they were derived from the philosophies of two singular historical figures. Both Freud and Krafft-Ebing were psychiatrists; their observations on sadism and masochism were dependent on psychiatric patients, and their models were built on the assumption of psychopathology. BDSM activists argue that it is illogical to attribute human behavioural phenomena as complex as sadism and masochism to the "inventions" of two historic individuals. Advocates of BDSM have sought to distinguish themselves from widely held notions of antiquated psychiatric theory by the adoption of the term "BDSM" as a distinction from the now common usage of those psychological terms, abbreviated as "S&M".
Behavioural and physiological aspects. BDSM is commonly mistaken as being "all about pain". Freud was confounded by the complexity and counterintuitiveness of practitioners' doing things that are self-destructive and painful. Rather than pain, BDSM practitioners are primarily concerned with power, humiliation, and pleasure. The aspects of D/s and B/D may not include physical suffering at all, but include the sensations experienced by different emotions of the mind. Of the three categories of BDSM, only sadomasochism specifically requires pain, but this is typically a means to an end, as a vehicle for feelings of humiliation, dominance, etc. In psychology, this aspect becomes a deviant behaviour once the act of inflicting or experiencing pain becomes a substitute for or the main source of sexual pleasure. In its most extreme, the preoccupation on this kind of pleasure can lead participants to view humans as insensate means of sexual gratification. Dominance and submission of power are an entirely different experience, and are not always psychologically associated with physical pain. Many BDSM activities involve no pain or humiliation, but just the exchange of power and control. During the activities, the participants may feel endorphin effects comparable to "runner's high" and to the afterglow of orgasm. The corresponding trance-like mental state is also called "subspace", for the submissive, and "domspace", for the dominant. Some use "body stress" to describe this physiological sensation. The experience of algolagnia is important, but is not the only motivation for many BDSM practitioners. The philosopher Edmund Burke called the sensation of pleasure derived from pain "sublime". Couples engaging in consensual BDSM tend to show hormonal changes that indicate decreases in stress and increases in emotional bonding.
There is an array of BDSM practitioners who take part in sessions in which they do not receive any personal gratification. They enter such situations solely with the intention to allow their partners to indulge their own needs or fetishes. Professional dominants do this in exchange for money, but non-professionals do it for the sake of their partners. In some BDSM sessions, the top exposes the bottom to a range of sensual experiences, such as pinching; biting; scratching with fingernails; erotic spanking; erotic electrostimulation; and the use of crops, whips, liquid wax, ice cubes, and Wartenberg wheels. Fixation by handcuffs, ropes, or chains may occur. The repertoire of possible "toys" is limited only by the imagination of both partners. To some extent, everyday items, such as clothespins, wooden spoons, and plastic wrap, are used in sex play. It is commonly considered that a pleasurable BDSM experience during a session depends strongly on the top's competence and experience and the bottom's physical and mental state. Trust and sexual arousal help the partners enter a shared mindset.
Types of play. Following are some of the types of BDSM play: Safety. Besides safe sex, BDSM sessions often require a wider array of safety precautions than vanilla sex (sexual behaviour without BDSM elements). To ensure consent related to BDSM activity, pre-play negotiations are commonplace, especially among partners who do not know each other very well. In practice, pick-up scenes at clubs or parties may sometimes be low in negotiation (much as pick-up sex from singles bars may not involve much negotiation or disclosure). These negotiations concern the interests and fantasies of each partner and establish a framework of both acceptable and unacceptable activities. This kind of discussion is a typical "unique selling proposition" of BDSM sessions and quite commonplace. Additionally, safewords are often arranged to provide for an immediate stop of any activity if any participant should so desire. Safewords are words or phrases that are called out when things are either not going as planned or have crossed a threshold one cannot handle. They are something both parties can remember and recognize and are, by definition, not words commonly used playfully during any kind of scene. Words such as "no", "stop", and "don't", are often inappropriate as a safeword if the roleplaying aspect includes the illusion of non-consent.
"The traffic light system" (TLS) is the most commonly used set of safewords. At most clubs and group-organized BDSM parties and events, dungeon monitors (DMs) provide an additional safety net for the people playing there, ensuring that house rules are followed and safewords respected. BDSM participants are expected to understand practical safety aspects, such as the potential for harm to body parts. Contusion or scarring of the skin can be a concern. Using crops, whips, or floggers, the top's fine motor skills and anatomical knowledge can make the difference between a satisfying session for the bottom and a highly unpleasant experience that may even entail severe physical harm. The very broad range of BDSM "toys" and physical and psychological control techniques often requires a far-reaching knowledge of details related to the requirements of the individual session, such as anatomy, physics, and psychology. Despite these risks, BDSM activities usually result in far less severe injuries than sports like boxing and football, and BDSM practitioners do not visit emergency rooms any more often than the general population.
It is necessary to be able to identify each person's psychological "squicks" or triggers in advance to avoid them. Such losses of emotional balance due to sensory or emotional overload are a fairly commonly discussed issue. It is important to follow participants' reactions empathetically and continue or stop accordingly. For some players, sparking "freakouts" or deliberately using triggers may be the desired outcome. Safewords are one way for BDSM practices to protect both parties. However, partners should be aware of each other's psychological states and behaviours to prevent instances where the "freakouts" prevent the use of safewords. After any BDSM activities, it is important that the participants go through sexual aftercare, to process and calm down from the activity. After the sessions, participants can need aftercare because their bodies have experienced trauma and they need to mentally come out of the role play. Social aspects. Types of relationships.
Amongst the respondents, it was typically the bottoms who wanted to play harder, and be more restricted into their roles when there was a difference in desire to play in the relationship. The author of the study, Bert Cutler, speculated that tops may be less often in the mood to play due to the increased demand for responsibility on their part: being aware of the safety of the situation and prepared to remove the bottom from a dangerous scenario, being conscious of the desires and limits of the bottom, and so on. The author of the study stressed that successful long-term BDSM relationships came after "early and thorough disclosure" from both parties of their BDSM interests. Many of those engaged in long-term BDSM relationships learned their skills from larger BDSM organizations and communities. There was a lot of discussion by the respondents on the amount of control the top possessed in the relationships but "no discussion of being better, or smarter, or of more value" than the bottom. Couples were generally of the same mind of whether or not they were in an ongoing relationship, but in such cases, the bottom was not locked up constantly, but that their role in the context of the relationship was always present, even when the top was doing non-dominant activities such as household chores, or the bottom being in a more dominant position. In its conclusion the study states:
The study further goes on to list three aspects that made the successful relationships work: early disclosure of interests and continued transparency, a commitment to personal growth, and the use of the dominant/submissive roles as a tool to maintain the relationship. In closing remarks, the author of the study theorizes that due to the serious potential for harm, couples in BDSM relationships develop increased communication that may be higher than in mainstream relationships. A professional dominatrix or professional dominant, often referred to within the culture as a "pro-dom(me)", offers services encompassing the range of bondage, discipline, and dominance in exchange for money. The term "dominatrix" is little-used within the non-professional BDSM scene. A non-professional dominant woman is more commonly referred to simply as a "domme", "dominant", or "femdom" (short for female dominance). Professional submissives ("pro-subs"), although far more rare, do exist. Scenes. In BDSM, a "scene" is the stage or setting where BDSM activity takes place, as well as the activity itself. The physical place where a BDSM activity takes place is usually called a dungeon, though some prefer less dramatic terms, including "playspace" or "club". A BDSM activity can, but need not, involve sexual activity or sexual roleplay. A characteristic of many BDSM relationships is the power exchange from the bottom to the dominant partner, and bondage features prominently in BDSM scenes and sexual roleplay.
"The Scene" (including use of the definite article "the") is also used in the BDSM community to refer to the BDSM community as a whole. Thus someone who is on "the Scene", and prepared to play in public, might take part in "a scene" at a public play party. A scene can take place in private between two or more people and can involve a domestic arrangement, such as servitude or a casual or committed lifestyle master/slave relationship. BDSM elements may involve settings of slave training or punishment for breaches of instructions. A scene can also take place in a club, where the play can be viewed by others. When a scene takes place in a public setting, it may be because the participants enjoy being watched by others, or because of the equipment available, or because having third parties present adds safety for play partners who have only recently met. Etiquette. Most standard social etiquette rules still apply when at a BDSM event, such as not intimately touching someone you do not know, not touching someone else's belongings (including toys), and abiding by dress codes. Many events open to the public also have rules addressing alcohol consumption, recreational drugs, cell phones, and photography.
A specific scene takes place within the general conventions and etiquette of BDSM, such as requirements for mutual consent and agreement as to the limits of any BDSM activity. This agreement can be incorporated into a formal contract. In addition, most clubs have additional rules which regulate how onlookers may interact with the actual participants in a scene. As is common in BDSM, these are founded on the catchphrase "safe, sane, and consensual". Parties and clubs. BDSM play parties are events in which BDSM practitioners and other similarly interested people meet in order to communicate, share experiences and knowledge, and to "play" in an erotic atmosphere. BDSM parties show similarities to ones in the dark culture, being based on a more or less strictly enforced dress code; often clothing made of latex, leather or vinyl/PVC, lycra and so on, emphasizing the body's shape and the primary and secondary sexual characteristics. The requirement for such dress codes differ. While some events have none, others have a policy in order to create a more coherent atmosphere and to prevent outsiders from taking part.
At these parties, BDSM can be publicly performed on a stage, or more privately in separate "dungeons". A reason for the relatively fast spread of this kind of event is the opportunity to use a wide range of "playing equipment", which in most apartments or houses is unavailable. Slings, St. Andrew's crosses (or similar restraining constructs), spanking benches, and punishing supports or cages are often made available. The problem of noise disturbance is also lessened at these events, while in the home setting many BDSM activities can be limited by this factor. In addition, such parties offer both exhibitionists and voyeurs a forum to indulge their inclinations without social criticism. Sexual intercourse is not permitted within most public BDSM play spaces or not often seen in others, because it is not the emphasis of this kind of play. In order to ensure the maximum safety and comfort for the participants, certain standards of behaviour have evolved; these include aspects of courtesy, privacy, respect and safewords. Today BDSM parties are taking place in most of the larger cities in the Western world.
This scene appears particularly on the Internet, in publications, and in meetings such as at fetish clubs (like Torture Garden), SM parties, gatherings called munches, and erotic fairs like Venus Berlin. The annual Folsom Street Fair held in San Francisco is the world's largest BDSM event. It has its roots in the gay leather movement. The weekend-long festivities include a wide range of sadomasochistic erotica in a public clothing optional space between 8th and 13th streets with nightly parties associated with the organization. There are also conventions such as Living in Leather and Black Rose. Psychology. Research indicates that there is no evidence that a preference for BDSM is a consequence of childhood abuse. Some reports suggest that people abused as children may have more BDSM injuries and have difficulty with safe words being recognized as meaning stop the previously consensual behaviour; thus, it is possible that people choosing BDSM as part of their lifestyle, who also were previously abused, may have had more police or hospital reports of injuries. In one study of three online surveys, many transgender adults remarked that BDSM influenced their individual experience of gender.
Joseph Merlino, author and psychiatry adviser to the "New York Daily News", said in an interview that a sadomasochistic relationship, as long as it is consensual, is not a psychological problem: Some psychologists agree that experiences during early sexual development can have a profound effect on the character of sexuality later in life. Sadomasochistic desires, however, seem to form at a variety of ages. Some individuals report having had them before puberty, while others do not discover them until well into adulthood. According to one study, the majority of male sadomasochists (53%) developed their interest before the age of 15, while the majority of females (78%) developed their interest afterward (Breslow, Evans, and Langley 1985). The prevalence of sadomasochism within the general population is unknown. Despite female sadists being less visible than males, some surveys have resulted in comparable amounts of sadistic fantasies between females and males. The results of such studies demonstrate that one's sex does not determine preference for sadism.
Following a phenomenological study of nine individuals involved in sexual masochistic sessions who regarded pain as central to their experience, sexual masochism was described as an addiction-like tendency, with several features resembling that of drug addiction: craving, intoxication, tolerance and withdrawal. It was also demonstrated how the first masochistic experience is placed on a pedestal, with subsequent use aiming at retrieving this lost sensation, much as described in the descriptive literature on addiction. Prevalence. BDSM occurs among people of all genders and sexual orientations, and in varied occurrences and intensities. The spectrum ranges from couples with no connections to the subculture outside of their bedrooms or homes, without any awareness of the concept of BDSM, playing "tie-me-up-games", to public scenes on St. Andrew's crosses at large events such as the Folsom Street Fair in San Francisco. Estimation on the overall percentage of BDSM-related sexual behaviour varies. Alfred Kinsey stated in his 1953 nonfiction book "Sexual Behavior in the Human Female" that 12% of females and 22% of males reported having an erotic response to a sadomasochistic story. In that book erotic responses to being bitten were given as:
A non-representative survey on the sexual behaviour of American students published in 1997 and based on questionnaires had a response rate of about 8–9%. Its results showed 15% of homosexual and bisexual males, 21% of lesbian and female bisexual students, 11% of heterosexual males and 9% of female heterosexual students committed to BDSM related fantasies. In all groups the level of practical BDSM experiences were around 6%. Within the group of openly lesbian and bisexual females, the quote was significantly higher, at 21%. Independent of their sexual orientation, about 12% of all questioned students, 16% of lesbians and female bisexuals and 8% of heterosexual males articulated an interest in spanking. Experience with this sexual behaviour was indicated by 30% of male heterosexuals, 33% of female bisexuals and lesbians, and 24% of the male gay and bisexual men and female heterosexual women. Even though this study was not considered representative, other surveys indicate similar dimensions in differing target groups.
A representative study done from 2001 to 2002 in Australia found that 1.8% of sexually active people (2.2% men, 1.3% women but no significant sex difference) had engaged in BDSM activity in the previous year. Of the entire sample, 1.8% of men and 1.3% of women had been involved in BDSM. BDSM activity was significantly more likely among bisexuals and homosexuals of both sexes. But among men in general, there was no relationship effect of age, education, language spoken at home or relationship status. Among women, in this study, activity was most common for those between 16 and 19 years of age and least likely for females over 50 years. Activity was also significantly more likely for women who had a regular partner they did not live with, but was not significantly related with speaking a language other than English or education. Another representative study, published in 1999 by the German Institut für rationale Psychologie, found that about 2/3 of the interviewed women stated a desire to be at the mercy of their sexual partners from time to time. 69% admitted to fantasies dealing with sexual submissiveness, 42% stated interest in explicit BDSM techniques, 25% in bondage. A 1976 study in the general US population suggests three per cent have had positive experiences with Bondage or master-slave roleplaying. Overall 12% of the interviewed females and 18% of the males were willing to try it. A 1990 Kinsey Institute report stated that 5% to 10% of Americans occasionally engage in sexual activities related to BDSM, 11% of men and 17% of women reported trying bondage. Some elements of BDSM have been popularized through increased media coverage since the middle 1990s. Thus both black leather clothing, sexual jewelry such as chains and dominance roleplay appear increasingly outside of BDSM contexts.
According to yet another survey of 317,000 people in 41 countries, about 20% of the surveyed have at least used masks, blindfolds or other bondage utilities once, and 5% explicitly connected themselves with BDSM. In 2004, 19% mentioned spanking as one of their practices and 22% confirmed the use of blindfolds or handcuffs. A 1985 study found 52 out of 182 female respondents (28%) were involved in sadomasochistic activities. A 2009 study on two separate samples of male undergraduate students in Canada found that 62 to 65%, depending on the sample, had entertained sadistic fantasies, and 22 to 39% engaged in sadistic behaviours during sex. The figures were 62 and 52% for bondage fantasies, and 14 to 23% for bondage behaviours. A 2014 study involving a mixed sample of Canadian college students and online volunteers, both male and female, reported that 19% of male samples and 10% of female samples rated the sadistic scenarios described in a questionnaire as being at least "slightly arousing" on a scale that ranged from "very repulsive" to "very arousing"; the difference was statistically significant.
A 2014 study involving a mixed sample of Canadian college students and online volunteers, both male and female, reported that 19% of male samples and 10% of female samples rated the sadistic scenarios described in a questionnaire as being at least "slightly arousing" on a scale that ranged from "very repulsive" to "very arousing"; the difference was statistically significant. The corresponding figures for the masochistic scenarios were 15% for male students and 17% for female students, a non-significant difference. In a 2011 study on 367 middle-aged and elderly men recruited from the broader community in Berlin, 21.8% of the men self-reported sadistic fantasies and 15.5% sadistic behaviors; 24.8% self-reported any such fantasy and/or behavior. The corresponding figures for self-reported masochism were 15.8% for fantasy, 12.3% for behaviour, and 18.5% for fantasy and/or behaviour.
Recent surveys on the spread of BDSM fantasies and practices show strong variations in the range of their results. Researchers believe that 5 to 25 per cent of the population practices sexual behaviour related to pain or dominance and submission. The population with related fantasies is believed to be even larger. Medical categorization. Reflecting changes in social norms, modern medical opinion is now moving away from regarding BDSM activities as medical disorders, unless they are nonconsensual or involve significant distress or harm. In 1995, Denmark became the first European Union country to have completely removed sadomasochism from its national classification of diseases. This was followed by Sweden in 2009, Norway in 2010, Finland in 2011, and Iceland in 2015. DSM. In the past, the Diagnostic and Statistical Manual of Mental Disorders (DSM), the American Psychiatric Association's manual, defined some BDSM activities as sexual disorders. Following campaigns from advocacy organizations including the National Coalition for Sexual Freedom, the current version of the DSM, DSM-5, excludes consensual BDSM from diagnosis when the sexual interests cause no harm or distress.
ICD. The World Health Organization's International Classification of Diseases (ICD) has changed in regard to BDSM in recent years. In Europe, an organization called worked to remove sadomasochism from the ICD. On 18 June 2018, the WHO (World Health Organization) published ICD-11, in which sadomasochism, together with fetishism and fetishistic transvestism (cross-dressing for sexual pleasure) are now removed as psychiatric diagnoses. Moreover, discrimination against fetish-having and BDSM individuals is considered inconsistent with human rights principles endorsed by the United Nations and The World Health Organization. The classifications of sexual disorders reflect contemporary sexual norms and have moved from a model of pathologization or criminalization of non-reproductive sexual behaviors to a model that reflects sexual well-being and pathologizes the absence or limitation of consent in sexual relations. Coming out. Some people who are interested in or curious about BDSM decide to come out of the closet, although many sadomasochists remain closeted. Depending upon a survey's participants, about 5 to 25 per cent of the US population show affinity to the subject. Other than a few artists and writers, practically no celebrities are publicly known as sadomasochists.
Public knowledge of one's BDSM lifestyle can have detrimental vocational and social effects for sadomasochists. Many face severe professional consequences or social rejection if they are exposed, either voluntarily or involuntarily, as sadomasochists. Within feminist circles, the discussion is split roughly into two camps: some who see BDSM as an aspect or reflection of oppression (for example, Alice Schwarzer) and, on the other side, pro-BDSM feminists, often grouped under the banner of sex-positive feminism (see Samois); both of them can be traced back to the 1970s. Some feminists have criticized BDSM for eroticizing power and violence and reinforcing misogyny. They argue that women who engage in BDSM are making a choice that is ultimately bad for women. Feminist defenders of BDSM argue that consensual BDSM activities are enjoyed by many women and validate the sexual inclinations of these women. They argue that there is no connection between consensual kinky activities and sex crimes, and that feminists should not attack other women's sexual desires as being "anti-feminist". They also state that the main point of feminism is to give an individual woman free choices in her life; which includes her sexual desire. While some feminists suggest connections between consensual BDSM scenes and non-consensual rape and sexual assault, other sex-positive ones find the notion insulting to women.
Roles are not fixed to gender, but personal preferences. The dominant partner in a heterosexual relationship may be the woman rather than the man, or BDSM may be part of male/male or female/female sexual relationships. Finally, some people switch, taking either a dominant or submissive role on different occasions. Several studies investigating the possibility of a correlation between BDSM pornography and the violence against women also indicate a lack of correlation. In 1991, a lateral survey came to the conclusion that between 1964 and 1984, despite the increase in amount and availability of sadomasochistic pornography in the U.S., Germany, Denmark and Sweden, there is no correlation with the national number of rapes to be found. Operation Spanner in the U.K. proves that BDSM practitioners still run the risk of being stigmatized as criminals. In 2003, the media coverage of Jack McGeorge showed that simply participating and working in BDSM support groups poses risks to one's job, even in countries where no law restricts it. Here a clear difference can be seen to the situation of homosexuality. The psychological strain appearing in some individual cases is normally neither articulated nor acknowledged in public. Nevertheless, it leads to a difficult psychological situation in which the person concerned can be exposed to high levels of emotional stress.
In the stages of "self-awareness", he or she realizes their desires related to BDSM scenarios or decides to be open for such. Some authors call this "internal coming-out". Two separate surveys on this topic independently came to the conclusion that 58 per cent and 67 per cent of the sample respectively, had realized their disposition before their 19th birthday. Other surveys on this topic show comparable results. Independent of age, coming-out can potentially result in a difficult life crisis, sometimes leading to thoughts or acts of suicide. While homosexuals have created support networks in the last decades, sadomasochistic support networks are just starting to develop in most countries. In German-speaking countries they are only moderately more developed. The Internet is the prime contact point for support groups today, allowing for local and international networking. In the U.S., Kink Aware Professionals (KAP) a privately funded, non-profit service provides the community with referrals to psychotherapeutic, medical, and legal professionals who are knowledgeable about and sensitive to the BDSM, fetish, and leather community. In the U.S. and the U.K., the Woodhull Freedom Foundation & Federation, National Coalition for Sexual Freedom (NCSF) and Sexual Freedom Coalition (SFC) have emerged to represent the interests of sadomasochists. The German Bundesvereinigung Sadomasochismus is committed to the same aim of providing information and driving press relations. In 1996, the website and mailing list Datenschlag went online in German and English providing the largest bibliography, as well as one of the most extensive historical collections of sources related to BDSM.
Social (non-medical) research. Richters et al. (2008) found that people who engaged in BDSM were more likely to have experienced a wider range of sexual practices (e.g., oral or anal sex, more than one partner, group sex, phone sex, viewed pornography, used a sex toy, fisting, etc.). They were, however, not any more likely to have been coerced, unhappy, anxious, or experiencing sexual difficulties. On the contrary, men who had engaged in BDSM scored lower on a psychological distress scale than men who did not. There have been few studies on the psychological aspects of BDSM using modern scientific standards. Psychotherapist Charles Moser has said there is no evidence for the theory that BDSM has common symptoms or any common psychopathology, emphasizing that there is no evidence that BDSM practitioners have any special psychiatric other problems based on their sexual preferences.
Moser's results are further supported by a 2008 Australian study by Richters "et al." on the demographic and psychosocial features of BDSM participants. The study found that BDSM practitioners were no more likely to have experienced sexual assault than the control group, and were not more likely to feel unhappy or anxious. The BDSM males reported higher levels of psychological well-being than the controls. It was concluded that "BDSM is simply a sexual interest or subculture attractive to a minority, not a pathological symptom of past abuse or difficulty with 'normal' sex." Gender differences in research. Several recent studies have been conducted on the gender differences and personality traits of BDSM practitioners.
Several recent studies have been conducted on the gender differences and personality traits of BDSM practitioners. In contrast, 46.6% of men prefer the submissive role, 24% consider themselves to be switches and 29.5% prefer the dominant role. They concluded that "men more often display an engagement in dominant practices, whereas females take on the submissive part. This result is inline with a recent study about mate preferences that has shown that women have a generally higher preference for a dominant partner than men do (Giebel, Moran, Schawohl, & Weierstall, 2015). Women also prefer dominant men, and even men who are aggressive, for a short-term relationship and for the purpose of sexual intercourse (Giebel, Weierstall, Schauer, & Elbert, 2013)". Similarly, studies on sexual fantasy differences between men and women show the latter prefer submissive and passive fantasies over dominant and active ones, with rape and force being common.
Gender differences in masochistic scripts. One common belief of BDSM and kink is that women are more likely to take on masochistic roles than men. Roy Baumeister (2010) had more male masochists in his study than female, and fewer male dominants than female. The lack of statistical significance in these gender differences suggests that no assumptions should be made regarding gender and masochistic roles in BDSM. One explanation why we might think otherwise lies in our social and cultural ideals about femininity; masochism may emphasize certain stereotypically feminine elements through activities like feminization of men and ultra-feminine clothing for women. But such tendencies of the submissive masochistic role should not be interpreted as a connection between it and the stereotypical female role—many masochistic scripts do not include any of these tendencies. Baumeister found that masochistic males experienced greater: severity of pain, frequency of humiliation (status-loss, degrading, oral), partner infidelity, active participation by other persons, and cross-dressing. Trends also suggested that male masochism included more bondage and oral sex than female (though the data was not significant). Female masochists, on the other hand, experienced greater: frequency in pain, pain as punishment for 'misdeeds' in the relationship context, display humiliation, genital intercourse, and presence of non-participating audiences. The exclusiveness of dominant males in a heterosexual relationship happens because, historically, men in power preferred multiple partners. Finally, Baumeister observes a contrast between the 'intense sensation' focus of male masochism to a more 'meaning and emotion' centred female masochistic script.
Prior argues that although some of these women may appear to be engaging in traditional subordinate or submissive roles, BDSM allows women in both dominant and submissive roles to express and experience personal power through their sexual identities. In a study that she conducted in 2013, she found that the majority of the women she interviewed identified as bottom, submissive, captive, or slave/sex slave. In turn, Prior was able to answer whether or not these women found an incongruity between their sexual identities and feminist identity. Her research found that these women saw little to no incongruity, and in fact felt that their feminist identity supported identities of submissive and slave. For them, these are sexually and emotionally fulfilling roles and identities that, in some cases, feed other aspects of their lives. Prior contends that third wave feminism provides a space for women in BDSM communities to express their sexual identities fully, even when those identities seem counter-intuitive to the ideals of feminism. Furthermore, women who do identify as submissive, sexually or otherwise, find a space within BDSM where they can fully express themselves as integrated, well-balanced, and powerful women.
Women in S/M culture. Levitt, Moser, and Jamison's 1994 study provides a general, if outdated, description of characteristics of women in the sadomasochistic (S/M) subculture. They state that women in S/M tend to have higher education, become more aware of their desires as young adults, are less likely to be married than the general population. The researchers found the majority of females identified as heterosexual and submissive, a substantial minority were versatile—able to switch between dominant and submissive roles—and a smaller minority identified with the dominant role exclusively. Oral sex, bondage and master-slave script were among the most popular activities, while feces/watersports were the least popular. Orientation observances in research. BDSM is considered by some of its practitioners to be a sexual orientation. The BDSM and kink scene is more often seen as a diverse pansexual community. Often this is a non-judgmental community where gender, sexuality, orientation, preferences are accepted as is or worked at to become something a person can be happy with. In research, studies have focused on bisexuality and its parallels with BDSM, as well as gay-straight differences between practitioners.
Asexuality. It has been suggested that some asexual people have found a language for navigating relationships through BDSM. Bisexuality. In Steve Lenius' original 2001 paper, he explored the acceptance of bisexuality in a supposedly pansexual BDSM community. The reasoning behind this is that 'coming-out' had become primarily the territory of the gay and lesbian, with bisexuals feeling the push to be one or the other (and being right only half the time either way). What he found in 2001, was that people in BDSM were open to discussion about the topic of bisexuality and pansexuality and all controversies they bring to the table, but personal biases and issues stood in the way of actively using such labels. A decade later, Lenius (2011) looks back on his study and considers if anything has changed. He concluded that the standing of bisexuals in the BDSM and kink community was unchanged, and believed that positive shifts in attitude were moderated by society's changing views towards different sexualities and orientations. But Lenius (2011) does emphasize that the pansexual promoting BDSM community helped advance greater acceptance of alternative sexualities.
Brandy Lin Simula (2012), on the other hand, argues that BDSM actively resists gender-conforming and identified three different types of BDSM bisexuality: gender-switching, gender-based styles (taking on a different gendered style depending on the gender of partner when playing), and rejection of gender (resisting the idea that gender matters in their play partners). Simula (2012) explains that practitioners of BDSM routinely challenge our concepts of sexuality by pushing the limits on pre-existing ideas of sexual orientation and gender norms. For some, BDSM and kink provides a platform in creating identities that are fluid, ever-changing. Comparison between gay and straight men in S/M. Demographically, Nordling et al.'s (2006) study found no differences in age, but 43% of gay male respondents compared to 29% of straight males had university-level education. The gay men also had higher incomes than the general population and tended to work in white-collar jobs while straight men tended toward blue-collar ones. Because there were not enough female respondents (22), no conclusions could be drawn from them.
Sexually speaking, the same 2006 study by Nordling et al. found that gay males were aware of their S/M preferences and took part in them at an earlier age, preferring leather, anal sex, rimming, dildos and special equipment or uniform scenes. In contrast, straight men preferred verbal humiliation, mask and blindfolds, gags, rubber/latex outfits, caning, vaginal sex, straitjackets, and cross-dressing among other activities. From the questionnaire, researchers were able to identify four separate sexual themes: hyper-masculinity, giving and receiving pain, physical restriction (i.e. bondage), and psychological humiliation. Gay men preferred activities that tended towards hyper-masculinity while straight men showed greater preference for humiliation, significantly higher master/madame-slave role play at ≈84%. Though there were not enough female respondents to draw a similar conclusion with, the fact that there is a difference in gay and straight men suggests strongly that S/M (and BDSM in general) can not be considered a homogenous phenomenon. As Nordling et al. (2006) puts it, "People who identify as sadomasochists mean different things by these identifications." (54)
History of psychotherapy and current recommendations. Psychiatry has an insensitive history in the area of BDSM. There have been many involvements by institutions of political power to marginalize subgroups and sexual minorities. Mental health professionals have a long history of holding negative assumptions and stereotypes about the BDSM community. Beginning with the DSM-II, Sexual Sadism and Sexual Masochism were listed as sexually deviant behaviours. Sadism and masochism were also found in the personality disorder section. This negative assumption has not changed significantly which is evident in the continued inclusion of Sexual Sadism and Sexual Masochism as paraphilias in the DSM-IV-TR. The DSM-V, however, has depathologized the language around paraphilias in a way that signifies "the APA’s intent to not demand treatment for healthy consenting adult sexual expression". Still, biases and misinformation can result in pathologizing and unintentional harm to clients who identify as sadists and/or masochists and medical professionals who have been trained under older editions of the DSM can be slow to change in their ways of clinical practice.
According to Kolmes et al. (2006), major themes of biased and inadequate care to BDSM clients are: These same researchers suggested that therapists should be open to learning more about BDSM, to show comfort in talking about BDSM issues, and to understand and promote "safe, sane, consensual" BDSM. There has also been research which suggests BDSM can be a beneficial way for victims of sexual assault to deal with their trauma, most notably by Corie Hammers, but this work is limited in scope and, to date, has not undergone empirical testing as a treatment. Clinical issues. Nichols (2006) compiled some common clinical issues: countertransference, non-disclosure, coming out, partner/families, and bleed-through. Countertransference is a common problem in clinical settings. Despite having no evidence, therapists may find themselves believing that their client's pathology is "self-evident". Therapists may feel intense disgust and aversive reactions. Feelings of countertransference can interfere with therapy. Another common problem is when clients conceal their sexual preferences from their therapists.
Feelings of countertransference can interfere with therapy. Another common problem is when clients conceal their sexual preferences from their therapists. This can compromise any therapy. To avoid non-disclosure, therapists are encouraged to communicate their openness in indirect ways with literature and artworks in the waiting room. Therapists can also deliberately bring up BDSM topics during the course of therapy. With less informed therapists, sometimes they over-focus on clients' sexuality which detracts from original issues such as family relationships, depression, etc. A special subgroup that needs counselling is the "newbie". Individuals just coming out might have internalized shame, fear, and self-hatred about their sexual preferences. Therapists need to provide acceptance, care, and model positive attitude; providing reassurance, psychoeducation, and bibliotherapy for these clients is crucial. The average age when BDSM individuals realize their sexual preference is around 26 years. Many people hide their sexuality until they can no longer contain their desires. The average age when BDSM individuals realize their sexual preference is around 26 years. Many people hide their sexuality until they can no longer contain their desires. However, they may have married or had children by this point.
History. Origins. Practices of BDSM survive from some of the oldest textual records in the world, associated with rituals to the goddess Inanna (Ishtar in Akkadian). Cuneiform texts dedicated to Inanna which incorporate domination rituals. In particular, she points to ancient writings such as Inanna and Ebih (in which the goddess dominates Ebih), and Hymn to Inanna describing cross-dressing transformations and rituals "imbued with pain and ecstasy, bringing about initiation and journeys of altered states of consciousness; punishment, moaning, ecstasy, lament and song, participants exhausting themselves in weeping and grief." During the 9th century BC, ritual flagellations were performed in Artemis Orthia, one of the most important religious areas of ancient Sparta, where the Cult of Orthia, a pre-Olympic religion, was practiced. Here, ritual flagellation called "diamastigosis" took place, in which young adolescent men were whipped in a ceremony overseen by the priestess. These are referred to by a number of ancient authors, including Pausanius (III, 16: 10–11).
One of the oldest graphical proofs of sadomasochistic activities is found in the Etruscan Tomb of the Whipping near Tarquinia, which dates to the 5th century BC. Inside the tomb, there is a fresco which portrays two men who flagellate a woman with a cane and a hand during an erotic situation. Another reference related to flagellation is to be found in the sixth book of the "Satires" of the ancient Roman Poet Juvenal (1st–2nd century A.D.), further reference can be found in Petronius's "Satyricon" where a delinquent is whipped for sexual arousal. Anecdotal narratives related to humans who have had themselves voluntary bound, flagellated or whipped as a substitute for sex or as part of foreplay reach back to the 3rd and 4th century BC. In Pompeii, a whip-mistress figure with wings is depicted on the wall of the Villa of Mysteries, as part of an initiation of a young woman into the Mysteries. The whip-mistress role drove the sacred initiation of ceremonial death and rebirth. The archaic Greek Aphrodite may too once have been armed with an implement, with archaeological evidence of armed Aphrodites known from a number of locations in Cythera, Acrocorinth and Sparta, and which may have been a whip.
The "Kama Sutra" of India describes four different kinds of hitting during lovemaking, the allowed regions of the human body to target and different kinds of joyful "cries of pain" practiced by bottoms. The collection of historic texts related to sensuous experiences explicitly emphasizes that impact play, biting and pinching during sexual activities should only be performed consensually since only some women consider such behavior to be joyful. From this perspective, the Kama Sutra can be considered one of the first written resources dealing with sadomasochistic activities and safety rules. Further texts with sadomasochistic connotation appear worldwide during the following centuries on a regular basis. There are anecdotal reports of people willingly being bound or whipped, as a prelude to or substitute for sex, during the 14th century. The medieval phenomenon of courtly love in all of its slavish devotion and ambivalence has been suggested by some writers to be a precursor of BDSM. Some sources claim that BDSM as a distinct form of sexual behavior originated at the beginning of the 18th century when Western civilization began medically and legally categorizing sexual behavior (see Etymology).
Flagellation practiced within an erotic setting has been recorded from at least the 1590s evidenced by a John Davies epigram, and references to "flogging schools" in Thomas Shadwell's "The Virtuoso" (1676) and Tim Tell-Troth's "Knavery of Astrology" (1680). Visual evidence such as mezzotints and print media is also identified revealing scenes of flagellation, such as "The Cully Flaug'd" from the British Museum collection. John Cleland's novel "Fanny Hill", published in 1749, incorporates a flagellation scene between the character's protagonist Fanny Hill and Mr Barville. A large number of flagellation publications followed, including "" (), promoting the names of women offering the service in a lecture room with rods and cat o' nine tails. Other sources give a broader definition, citing BDSM-like behavior in earlier times and other cultures, such as the medieval flagellates and the physical ordeal rituals of some Native American societies. BDSM ideas and imagery have existed on the fringes of Western culture throughout the 20th century. Robert Bienvenu attributes the origins of modern BDSM to three sources, which he names as "European Fetish" (from 1928), "American Fetish" (from 1934), and "Gay Leather" (from 1950). Another source are the sexual games played in brothels, which go back to the 19th century, if not earlier. Charles Guyette was the first American to produce and distribute fetish related material (costumes, footwear, photography, props and accessories) in the U.S. His successor, Irving Klaw, produced commercial sexploitation film and photography with a BDSM theme (most notably with Bettie Page) and issued fetish comics (known then as "chapter serials") by the now-iconic artists John Willie, Gene Bilbrew, and Eric Stanton.
Stanton's model Bettie Page became at the same time one of the first successful models in the area of fetish photography and one of the most famous pin-up girls of American mainstream culture. Italian author and designer Guido Crepax was deeply influenced by him, coining the style and development of European adult comics in the second half of the 20th century. The artists Helmut Newton and Robert Mapplethorpe are the most prominent examples of the increasing use of BDSM-related motives in modern photography and the public discussions still resulting from this. Alfred Binet first coined the term "erotic fetishism" in his 1887 book, "Du fétichisme dans l'amour" Richard von Krafft-Ebing saw BDSM interests as the end of a continuum. Leather movement. Leather has been a predominantly gay male term to refer to one fetish, but it can stand for many more. Members of the gay male leather community may wear leathers such as motorcycle leathers, or may be attracted to men wearing leather. Leather and BDSM are seen as two parts of one whole. Much of the BDSM culture can be traced back to the gay male leather culture, which formalized itself out of the group of men who were soldiers returning home after World War II (1939–1945). World War II was the setting where countless homosexual men and women tasted the life among homosexual peers. Post-war, homosexual individuals congregated in larger cities such as New York, Chicago, San Francisco, and Los Angeles. They formed leather clubs and bike clubs; some were fraternal services. The establishment of Mr. Leather Contest and Mr. Drummer Contest were made around this time. This was the genesis of the gay male leather community. Many of the members were attracted to extreme forms of sexuality, for which peak expression was in the pre-AIDS 1970s. This subculture is epitomized by the "Leatherman's Handbook" by Larry Townsend, published in 1972, which describes in detail the practices and culture of gay male sadomasochists in the late 1960s and early 1970s.
In the early 1980s, lesbians also joined the leathermen as a recognizable element of the gay leather community. They also formed leather clubs, but there were some gender differences, such as the absence of leatherwomen's bars. In 1981, the publication of "Coming to Power" by lesbian-feminist group Samois led to a greater knowledge and acceptance of BDSM in the lesbian community. By the 1990s, the gay men's and women's leather communities were no longer underground and played an important role in the kink community. Today, the leather movement is generally seen as a part of the BDSM-culture instead of as a development deriving from gay subculture, even if a huge part of the BDSM-subculture was gay in the past. In the 1990s, the so-called New Guard leather subculture evolved. This new orientation started to integrate psychological aspects into their play. The Leather Archives and Museum (LA&M) in Chicago was founded in 1991 by Chuck Renslow and Tony DeBlase as a “community archives, library, and museum of leather, kink, fetish, and BDSM history and culture.” The LA&M has an extensive collection of leather- and BDSM-related artifacts, including one of three original leather pride flags.
The San Francisco South of Market Leather History Alley consists of four works of art along Ringold Alley honoring leather culture; it opened in 2017. One of the works of art is metal bootprints along the curb which honor 28 people (including Steve McEachern, owner of the Catacombs, a gay and lesbian S/M fisting club, and Cynthia Slater, a founder of the Society of Janus, the second oldest BDSM organization in the United States) who were an important part of the leather communities of San Francisco. Internet. In the late 1980s, the Internet provided a way of finding people with specialized interests around the world as well as on a local level, and communicating with them anonymously. This brought about an explosion of interest and knowledge of BDSM, particularly on the usenet group alt.sex.bondage. When that group became too cluttered with spam, the focus moved to soc.subculture.bondage-bdsm. With an increased focus on forms of social media, FetLife was formed, which advertises itself as "a social network for the BDSM and fetish community". It operates similarly to other social media sites, with the ability to make friends with other users, events, and pages of shared interests.
In addition to traditional sex shops, which sell sex paraphernalia, there has also been an explosive growth of online adult toy companies that specialize in leather/latex gear and BDSM toys. Once a very niche market, there are now very few sex toy companies that do not offer some sort of BDSM or fetish gear in their catalog. Kinky elements seem to have worked their way into "vanilla" markets. The former niche expanded to an important pillar of the business with adult accessories. Today practically all suppliers of sex toys do offer items which originally found usage in the BDSM subculture. Padded handcuffs, latex and leather garments, as well as more exotic items like soft whips for fondling and TENS for erotic electro stimulation, can be found in catalogs aiming at classical vanilla target groups, indicating that former boundaries increasingly seem to shift. During the last years, the Internet also provides a central platform for networking among individuals who are interested in the subject. Besides countless private and commercial choices, there is an increasing number of local networks and support groups emerging. These groups often offer comprehensive background and health-related information for people who have been unwillingly outed as well as contact lists with information on psychologists, physicians and lawyers who are familiar with BDSM-related topics.
Legal status. Austria. Section 90 of the Austrian criminal code declares bodily injury (Sections 83–84) or the endangerment of physical security (Section 89) to not be subject to penalty in cases in which the victim has consented and the injury or endangerment does not offend moral sensibilities. Case law from the Austrian Supreme Court has consistently shown that bodily injury is only offensive to moral sensibilities, thus it is only punishable when a "serious injury" (damage to health or an employment disability lasting more than 24 days) or the death of the "victim" results. A "light injury" is generally considered "permissible" when the "victim" has consented to it. In cases of threats to bodily well-being, the standard depends on the probability that an injury will occur. If serious injury or even death would be a likely result of a threat being carried out, then even the threat itself is considered punishable. Canada. In 2004, a judge in Canada ruled that videos seized by the police featuring BDSM activities were not obscene and did not constitute violence, but a "normal and acceptable" sexual activity between two consenting adults.
In 2011, the Supreme Court of Canada ruled in "R. v. J.A." that a person must have an active mind during the specific sexual activity in order to legally consent. The Court ruled that it is a criminal offence to perform a sexual act on an unconscious person—whether or not that person consented in advance. Germany. According to Section 194 of the German criminal code, the charge of insult (slander) can only be prosecuted if the defamed person chooses to press charges. False imprisonment can be charged if the victim—when applying an objective view—can be considered to be impaired in their rights of free movement. According to Section 228, a person inflicting a bodily injury on another person with that person's permission violates the law only in cases where the act can be considered to have violated good morals in spite of permission having been given. On 26 May 2004, the Criminal Panel No. 2 of the Bundesgerichtshof (German Federal Court) ruled that sado-masochistically motivated physical injuries are not per se indecent and thus subject to Section 228.
Following cases in which sado-masochistic practices had been repeatedly used as pressure tactics against former partners in custody cases, the Appeals Court of Hamm ruled in February 2006 that sexual inclinations toward sado-masochism are no indication of a lack of capabilities for successful child-raising. Italy. In Italian law, BDSM is right on the border between crime and legality, and everything lies in the interpretation of the legal code by the judge. This concept is that anyone willingly causing "injury" to another person is to be punished. In this context, though, "injury" is legally defined as "anything causing a condition of illness", and "illness" is ill-defined itself in two different legal ways. The first is "any anatomical or functional alteration of the organism" (thus technically including little scratches and bruises too); the second is "a significant worsening of a previous condition relevant to organic and relational processes, requiring any kind of therapy". This could make it somewhat risky to play with someone, as later the "victim" may call foul play citing even an insignificant mark as evidence against the partner. Also, any injury requiring over 20 days of medical care must be denounced by the professional medic who discovers it, leading to automatic indictment of the person who caused it.
Nordic countries. In September 2010, a Swedish court acquitted a 32-year-old man of assault for engaging in consensual BDSM play with a 16-year-old girl (the age of consent in Sweden is 15). Norway's legal system has likewise taken a similar position, that safe and consensual BDSM play should not be subject to criminal prosecution. This parallels the stance of the mental health professions in the Nordic countries which have removed sadomasochism from their respective lists of psychiatric illnesses. Switzerland. The age of consent in Switzerland is 16 years, which also applies to BDSM play. Minors (i.e., those under 16) are not subject to punishment for BDSM play as long as the age difference between them is less than three years. Certain practices, however, require granting consent for light injuries, with only those over 18 permitted to give consent. On 1 April 2002, Articles 135 and 197 of the Swiss Criminal Code were tightened to make ownership of "objects or demonstrations [...] which depict sexual acts with violent content" a punishable offense. This law amounts to a general criminalization of sado-masochism since nearly every sado-masochist will have some kind of media that fulfills this criterion. Critics also object to the wording of the law which puts sado-masochists in the same category as pedophiles and pederasts.
United Kingdom. In British law, consent is an absolute defense to common assault, but not necessarily to actual bodily harm, where courts may decide that consent is not valid, as occurred in the case of "R v Brown". Accordingly, consensual activities in the U.K. may not constitute "assault occasioning actual or grievous bodily harm" in law. The Spanner Trust states that this is defined as activities which have caused injury "of a lasting nature" but that only a slight duration or injury might be considered "lasting" in law. The decision contrasts with the later case of "R v Wilson" in which conviction for non-sexual consensual branding within a marriage was overturned, the appeal court ruling that "R v Brown" was not an authority in all cases of consensual injury and criticizing the decision to prosecute. Following Operation Spanner, the European Court of Human Rights ruled in January 1999 in "Laskey, Jaggard and Brown v. United Kingdom" that no violation of Article 8 occurred because the amount of physical or psychological harm that the law allows between any two people, even consenting adults, is to be determined by the jurisdiction the individuals live in, as it is the State's responsibility to balance the concerns of public health and well-being with the amount of control a State should be allowed to exercise over its citizens. In the Criminal Justice and Immigration Bill 2007, the British Government cited the Spanner case as justification for criminalizing images of consensual acts, as part of its proposed criminalization of possession of "extreme pornography". Another contrasting case was that of Stephen Lock in 2013, who was cleared of actual bodily harm on the grounds that the woman consented. In this case, the act was deemed to be sexual.
United States. The United States Federal law does not list a specific criminal determination for consensual BDSM acts. Many BDSM practitioners cite the legal decision of "People v. Jovanovic", 95 N.Y.2d 846 (2000), or the "Cybersex Torture Case", which was the first U.S. appellate decision to hold (in effect) that one does not commit assault if the victim consents. However, many individual states do criminalize specific BDSM actions within their state borders. Some states specifically address the idea of "consent to BDSM acts" within their assault laws, such as the state of New Jersey, which defines "simple assault" to be "a disorderly persons offense unless committed in a fight or scuffle "entered into by mutual consent", in which case it is a petty disorderly persons offense". Oregon Ballot Measure 9 was a ballot measure in the U.S. state of Oregon in 1992, concerning sadism, masochism, gay rights, pedophilia, and public education, that drew widespread national attention. It would have added the following text to the Oregon Constitution:
It was defeated in the 3 November 1992 general election with 638,527 votes in favor, 828,290 votes against. The National Coalition for Sexual Freedom collects reports about punishment for sexual activities engaged in by consenting adults, and about its use in child custody cases. Cultural aspects. Today, the BDSM culture exists in most Western countries. This offers BDSM practitioners the opportunity to discuss BDSM relevant topics and problems with like-minded people. This culture is often viewed as a subculture, mainly because BDSM is often still regarded as "unusual" by some of the public. Many people hide their leaning from society since they are afraid of the incomprehension and of social exclusion. In contrast to frameworks seeking to explain sadomasochism through psychological, psychoanalytic, medical or forensic approaches, which seek to categorize behaviour and desires and find a root "cause", Romana Byrne suggests that such practices can be seen as examples of "aesthetic sexuality", in which a founding physiological or psychological impulse is irrelevant. Rather, sadism and masochism may be practiced through choice and deliberation, driven by certain aesthetic goals tied to style, pleasure, and identity. These practices, in certain circumstances and contexts, can be compared with the creation of art.
Symbols. One of the most commonly used symbols of the BDSM community is a derivation of a triskelion shape within a circle. Various forms of triskele have had many uses and many meanings in many cultures; its BDSM usage derives from the "Ring of O" in the classic book "Story of O". The BDSM Emblem Project claims copyright over one particular specified form of the triskelion symbol; other variants of the triskelion are free from such copyright claims. The triskelion as a BDSM symbol can easily be perceived as the three separate parts of the acronym BDSM; which are BD, DS, and SM (Bondage & Discipline, Dominance & Submission, Sadism & Masochism). They are three separate items, that are normally associated together. The leather pride flag, shown to the right, is a symbol for the leather subculture and also widely used within BDSM. In continental Europe, the "Ring of O" is widespread among BDSM practitioners. The BDSM rights flag, shown to the right, was designed by Tanos, a Master from the United Kingdom. It is partially loosely based on the design of the leather pride flag, and also includes a version of the BDSM Emblem (but not similar enough to fall within Steve Quagmyr's specific copyright claims for the Emblem). The BDSM rights flag is intended to represent the belief that people whose sexuality or relationship preferences include BDSM practices deserve the same human rights as everyone else, and should not be discriminated against for pursuing BDSM with consenting adults.
The flag is inspired by the leather pride flag and BDSM emblem but is specifically intended to represent the concept of BDSM rights and to be without the other symbols' restrictions against commercial use. It is designed to be recognizable by people familiar with either the leather pride flag or BDSM triskelion (or triskele) as "something to do with BDSM"; and to be distinctive whether reproduced in full colour, or in black and white (or another pair of colours). BDSM and fetish items and styles have been spread widely in Western societies' everyday life by different factors, such as avant-garde fashion, heavy metal, goth subculture, and science fiction TV series, and are often not consciously connected with their BDSM roots by many people. While it was mainly confined to the punk and BDSM subcultures in the 1990s, it has since spread into wider parts of Western societies. Theater. Although it would be possible to establish certain elements related to BDSM in classical theater, not until the emergence of contemporary theater would some plays have BDSM as the main theme. Exemplifying this are two works: one Austrian, one German, in which BDSM is not only incorporated but integral to the storyline of the play.
Literature. Although examples of literature catering to BDSM and fetishistic tastes were created in earlier periods, BDSM literature as it exists today cannot be found much earlier than World War II. The word "sadism" originates from the works of Donatien Alphonse François, Marquis de Sade, and the word "masochism" originates from Leopold von Sacher-Masoch, the author of "Venus in Furs". However, it is worth noting that the Marquis de Sade describes non-consensual abuse in his works, such as in "Justine". "Venus in Furs" describes a consensual dom-sub relationship. A central work in modern BDSM literature is undoubtedly "Story of O" (1954) by Anne Desclos under the pseudonym Pauline Réage. Other notable works include "9½ Weeks" (1978) by Elizabeth McNeill, some works of the writer Anne Rice ("Exit to Eden", and her "Claiming of Sleeping Beauty" series of books), Jeanne de Berg ("L'Image" (1956) dedicated to Pauline Réage), the Gor series by John Norman, and naturally all the works of Patrick Califia, Gloria Brame, the group Samois and many of the writer Georges Bataille ("Histoire de l'oeil-Story of the Eye", Madame Edwarda, 1937), as well as those of Bob Flanagan ("Slave Sonnets" (1986), "Fuck Journal" (1987), "A Taste of Honey" (1990)). A common part of many of the poems of Pablo Neruda is a reflection on feelings and sensations arising from the relations of EPE or erotic exchange of power. The "Fifty Shades" trilogy is a series of very popular erotic romance novels by E. L. James which involves BDSM; however, the novels have been criticized for their inaccurate and harmful depiction of BDSM. In the 21st century, a number of prestigious university presses, such as Duke University, Indiana University and University of Chicago, have published books on BDSM written by professors, thereby lending academic legitimacy to this once taboo topic.
Bash (Unix shell) In computing, Bash (short for ""Bourne Again SHell",") is an interactive command interpreter and command programming language developed for UNIX-like operating systems. Created in 1989 by Brian Fox for the GNU Project, it is supported by the Free Software Foundation and designed as a 100% free alternative for the Bourne shell (codice_1) and other proprietary Unix shells. Since its inception, Bash has gained widespread adoption and is commonly used as the default login shell for numerous Linux distributions. It holds historical significance as one of the earliest programs ported to Linux by Linus Torvalds, alongside the GNU Compiler (GCC). It is available on nearly all modern operating systems, making it a versatile tool in various computing environments. As a command-line interface (CLI), Bash operates within a terminal emulator, or text window, where users input commands to execute various tasks. It also supports the execution of commands from files, known as shell scripts, facilitating automation. In keeping with Unix shell conventions, Bash incorporates a rich set of features. The keywords, syntax, dynamically scoped variables, and other basic features of the language are all copied from the Bourne shell, (codice_1). Other features, e.g., history, are copied from the C shell, (codice_3), and the Korn Shell, (codice_4). It is a POSIX-compliant shell with extensions.
History. While Bash was developed for UNIX and UNIX-like operating systems, such as GNU/Linux, it is also available on Android, macOS, Windows, and numerous other current and historical operating systems. "Although there have been attempts to create specialized shells, the Bourne shell derivatives continue to be the primary shells in use." Features. List of Short Descriptions. As a command processor, Bash operates within a text window where users input commands to execute various tasks. It also supports the execution of commands from files, known as shell scripts, facilitating automation. In keeping with Unix shell conventions, Bash incorporates a rich set of features, including: Bash also offers... General Discussion. The Bash command syntax is a superset of the Bourne shell command syntax. Bash supports brace expansion, command line completion (Programmable Completion), basic debugging and signal handling (using codice_23) since bash 2.05a among other features. Bash can execute the vast majority of Bourne shell scripts without modification, with the exception of Bourne shell scripts stumbling into fringe syntax behavior interpreted differently in Bash or attempting to run a system command matching a newer Bash builtin, etc. Bash command syntax includes ideas drawn from the Korn Shell (ksh) and the C shell (csh) such as command line editing, command history (codice_73 command), the directory stack, the codice_74 and codice_75 variables, and POSIX command substitution syntax codice_76.