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Arrow (symbol)
An arrow is a graphical symbol, such as ← or →, or a pictogram, used to point or indicate direction. In its simplest form, an arrow is a triangle, chevron, or concave kite, usually affixed to a line segment or rectangle, and in more complex forms a representation of an actual arrow (e.g. ➵ U+27B5). The direction indicated by an arrow is the one along the length of the line or rectangle toward the single pointed end. History An older (medieval) convention is the manicule (pointing hand, 👈). Pedro Reinel in c. 1504 first used the fleur-de-lis as indicating north in a compass rose; the convention of marking the eastern direction with a cross is older (medieval). Use of the arrow symbol does not appear to pre-date the 18th century. An early arrow symbol is found in an illustration of Bernard Forest de Bélidor's treatise ''L'architecture hydraulique'', printed in France in 1737. The arrow is here used to illustrate the direction of the flow of water and of the wat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arrow Key
Arrow keys or cursor movement keys are buttons on a computer keyboard that are either programmed or designated to move the cursor in a specified direction. The term "cursor movement key" is distinct from "arrow key" in that the former term may refer to any of various keys on a computer keyboard designated for cursor movement, whereas "arrow keys" generally refers to one of four specific keys, typically marked with arrows. Arrow keys are typically located at the bottom of the keyboard to the left side of the numeric keypad, usually arranged in an inverted-T layout but also found in diamond shapes and linear shapes. Arrow keys are commonly used for navigating around documents and for playing games. The inverted-T layout was popularized by the Digital Equipment Corporation LK201 keyboard from 1982. Historical development Before the computer mouse was widespread, arrow keys were the primary way of moving a cursor on screen. Mouse keys is a feature that allows controlling a mouse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Backspace
Backspace () is the keyboard key that originally pushed the typewriter carriage one position backwards and in modern computer systems moves the display cursor one position backwards,"Backwards" means to the left for left-to-right languages. deletes the character at that position, and shifts back the text after that position by one position. Typewriter In someMany typewriters don't advance accent characters, so that no backspace is needed. However, it is still used e.g. for combining "o" with "/". typewriters, a typist would, for example, type a lowercase letter A with acute accent (á) by typing a lowercase letter A, backspace, and then the acute accent key. This technique (also known as overstrike) is the basis for such spacing modifiers in computer character sets such as the ASCII caret (^, for the circumflex accent). Backspace composition no longer works with typical modern digital displays or typesetting systems.There is no reason why a digital display or typesetting system cou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Assignment (computer Science)
In computer programming, an assignment statement sets and/or re-sets the value stored in the storage location(s) denoted by a variable name; in other words, it copies a value into the variable. In most imperative programming languages, the assignment statement (or expression) is a fundamental construct. Today, the most commonly used notation for this operation is ''x'' = ''expr'' (originally Superplan 1949–51, popularized by Fortran 1957 and C). The second most commonly used notation is ''x'' := ''expr'' (originally ALGOL 1958, popularised by Pascal). Many other notations are also in use. In some languages, the symbol used is regarded as an operator (meaning that the assignment statement as a whole returns a value). Other languages define assignment as a statement (meaning that it cannot be used in an expression). Assignments typically allow a variable to hold different values at different times during its life-span and scope. However, some languages (primarily strictly f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Converse Implication
In logic and mathematics, the converse of a categorical or implicational statement is the result of reversing its two constituent statements. For the implication ''P'' → ''Q'', the converse is ''Q'' → ''P''. For the categorical proposition ''All S are P'', the converse is ''All P are S''. Either way, the truth of the converse is generally independent from that of the original statement.Robert Audi, ed. (1999), ''The Cambridge Dictionary of Philosophy'', 2nd ed., Cambridge University Press: "converse". Implicational converse Let ''S'' be a statement of the form ''P implies Q'' (''P'' → ''Q''). Then the converse of ''S'' is the statement ''Q implies P'' (''Q'' → ''P''). In general, the truth of ''S'' says nothing about the truth of its converse, unless the antecedent ''P'' and the consequent ''Q'' are logically equivalent. For example, consider the true statement "If I am a human, then I am mortal." The converse of that statement is "If I am mortal, then I am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relative Direction
In geometry, a position or position vector, also known as location vector or radius vector, is a Euclidean vector that represents the position of a point ''P'' in space in relation to an arbitrary reference origin ''O''. Usually denoted x, r, or s, it corresponds to the straight line segment from ''O'' to ''P''. In other words, it is the displacement or translation that maps the origin to ''P'': :\mathbf=\overrightarrow The term "position vector" is used mostly in the fields of differential geometry, mechanics and occasionally vector calculus. Frequently this is used in two-dimensional or three-dimensional space, but can be easily generalized to Euclidean spaces and affine spaces of any dimension.Keller, F. J, Gettys, W. E. et al. (1993), p 28–29 Relative position The relative position of a point ''Q'' with respect to point ''P'' is the Euclidean vector resulting from the subtraction of the two absolute position vectors (each with respect to the origin): :\Delta \mathbf=\ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Medical Abbreviations
Abbreviations are used very frequently in medicine. They boost efficiency as long as they are used intelligently. The advantages of brevity should be weighed against the possibilities of obfuscation (making the communication harder for others to understand) and ambiguity (having more than one possible interpretation). Certain medical abbreviations are avoided to prevent mistakes, according to best practices (and in some cases regulatory requirements); these are flagged in the list of abbreviations used in medical prescriptions. Orthographic styling Periods (stops) Periods (stops) are often used in styling abbreviations. Prevalent practice in medicine today is often to forego them as unnecessary. * Example: ** ''Less common:'' The diagnosis was C.O.P.D. hronic obstructive pulmonary disease** ''More common:'' The diagnosis was COPD Plurals The prevalent way to represent plurals for medical acronyms and initialisms is simply to affix a lowercase ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arrow (other)
An arrow is a projectile launched from a bow. Arrow or arrows may also refer to: Symbols * Arrow (symbol) ** ↑ (other) ** → (other) ** ↓ (other) ** ← (other) Places * Arrow, Kentucky * Arrow, Warwickshire, England * Arrow River (New Zealand) * River Arrow, Wales * River Arrow, Worcestershire, England People * Arrow (musician) (1949–2010), calypso and soca musician * Gilbert John Arrow (1873–1948), English entomologist * Kenneth Arrow (1921–2017), American economist, joint winner of the 1972 Nobel Prize in Economics Arts, entertainment, and media Fictional entities * Arrow (comics), a superhero character, first appearing in 1938 * The Arrow, a fictional location, the first Dharma Initiative station in the television series ''Lost'' *Arrow, a character from Rudolph the Red-Nosed Reindeer: The Movie. Music Groups and labels * Arrows (Australian band), indie rock band established 2006 * Arrows (British band), 1970s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
↑ (other)
The symbol ↑, an upward pointing arrow, also called up arrow, uparrow, or upwards arrow, may refer to: Notation * ↑, a mathematical symbol for "undefined" * ↑, a notation of Knuth's up-arrow notation for very large integers * ↑, a mathematical game theory position ''Up'' * ↑ or Sheffer stroke, the logical connective "not both" or NAND * ↑, the APL function 'take' * "Increased" (and similar meanings), in medical notation * ↑, a chemical symbol for production of gas, which bubbles up. Character representations * ↑, upwards arrow, a Unicode arrow symbol * ↑, ↑, a HTML or XML character entity * ↑, codepoint 8A (hex) in EBCDIC Code page 293, used for writing APL * ↑, the glyph for character 94 (decimal) in ASCII until 1967, when it was replaced by the caret (^). See also * Ꙟ, an archaic Romanian Cyrillic letter * Arrow keys, on computer keyboards * Arrow (other) ** ↓ (other) ** → (other) → or -> may refer to: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
↓ (other)
The arrow symbol ↓ may refer to: * The downward direction, a relative direction * The keyboard cursor control key, an arrow key * A downwards arrow, a Unicode arrow symbol * Logical NOR, operator which produces a result that is the negation of logical OR * An undefined object, in mathematical well-definition * A comma category, in category theory * Down (game theory), a mathematical game * The ingressive sound, in phonetics * An APL function * "Decreased" (and similar meanings), in medical notation * The precipitation of an insoluble solid, in chemical notation See also * Down sign (other) * Arrow (other) ** ↑ (other) ** → (other) → or -> may refer to: * one of the arrow symbols, characters of Unicode * one of the arrow keys, on a keyboard * →, >, representing the assignment operator in various programming languages * ->, a Pointer operator in C and C++ where a->b i ... ** ← (other) {{disambiguation Logic sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
