Longman Dictionary of Contemporary English
Base or BASE may refer to:
In mathematics, a base (or basis) B for a topological spaceX with topologyT is a collection of open sets in T such that every open set in T can be written as a union of elements of B. We say that the base generates the topology T. Bases are useful because many properties of topologies can be reduced to statements about a base generating that topology, and because many topologies are most easily defined in terms of a base which generates them.
In chemistry, bases are substances that, in aqueous solution, are slippery to the touch, taste astringent, change the color of indicators (e.g., turn red litmus paper blue), react with acids to form salts, promote certain chemical reactions ( base catalysis), accept protons from any proton donor, and/or contain completely or partially displaceable OH ions. Examples of bases are the hydroxides of the alkali metals and alkaline earth metals ( NaOH, Ca(OH), etc.).
These particular substances produce hydroxide ions (OH) in aqueous solutions, and are thus classified as Arrhenius bases. For a substance to be classified as an Arrhenius base, it must produce hydroxide ions in an aqueous solution. In order to do so, Arrhenius believed the base must contain hydroxide in the formula. This makes the Arrhenius model limited, as it cannot explain the basic properties of aqueous solutions of ammonia (NH) or its organic derivatives ( amines). There are also bases that do not contain a hydroxide ion but nevertheless react with water, resulting in an increase in the concentration of the hydroxide ion. An example of this is the reaction between ammonia and water to produce ammonium and hydroxide. In this reaction ammonia is the base because it accepts a proton from the water molecule. Ammonia and other bases similar to it usually have the ability to form a bond with a proton due to the unshared pair of electrons that they possess. In the more general Brønsted–Lowry acid–base theory, a base is a substance that can accept hydrogen cations (H)—otherwise known as protons. In the Lewis model, a base is an electron pair donor.
In water, by altering the autoionization equilibrium, bases yield solutions in which the hydrogen ion activity is lower than it is in pure water, i.e., the water has a pH higher than 7.0 at standard conditions. A soluble base is called an alkali if it contains and releases OH ions quantitatively. However, it is important to realize that basicity is not the same as alkalinity. Metal oxides, hydroxides, and especially alkoxides are basic, and counteranions of weak acids are weak bases.
Bases can be thought of as the chemical opposite of acids. However, some strong acids are able to act as bases. Bases and acids are seen as opposites because the effect of an acid is to increase the hydroxonium (HO) concentration in water, whereas bases reduce this concentration. A reaction between an acid and base is called neutralization. In a neutralization reaction, an aqueous solution of a base reacts with an aqueous solution of an acid to produce a solution of water and salt in which the salt separates into its component ions. If the aqueous solution is saturated with a given salt solute, any additional such salt precipitates out of the solution.
The notion of a base as a concept in chemistry was first introduced by the French chemist Guillaume François Rouelle in 1754. He noted that acids, which at that time were mostly volatile liquids (like acetic acid), turned into solid salts only when combined with specific substances. Rouelle considered that such a substance serves as a "base" for the salt, giving the salt a "concrete or solid form".
In politics, the term base refers to a group of voters who almost always support a single party's candidates for elected office. Base voters are very unlikely to vote for the candidate of an opposing party, regardless of the specific views each candidate holds. In the United States, this is typically because high-level candidates must hold the same stances on key issues as a party's base in order to gain the party's nomination and thus be guaranteed ballot access. In the case of legislative elections, base voters often prefer to support their party's candidate against an otherwise appealing opponent in order to strengthen their party's chances of gaining a simple majority, typically the gateway to overarching power, in a legislature.
Base (mobile telephony provider)
BASE is the third largest of Belgium's three mobile telecommunications operators. It is a subsidiary of Telenet. It competes with Proximus and Orange Belgium. It was previously owned by KPN and sold to Telenet in 2015.
Base (Hiro Sokuto) is a fictional character, a mutant appearing in American comic books published by Marvel Comics. His first appearance was in Genetix #1.
Base is an international design, communications, audiovisual, copywriting and publishing firm established in 1993. The company has studios located in New York, Brussels, Santiago and Geneva.
In exponentiation, the base is the number b in an expression of the form b.
Base is the first EP of Korean boy band Shinee member Jonghyun, released on January 12, 2015 by S.M. Entertainment.
Base (group theory)
Let G be a finite permutation group acting on a set Ω. A sequence
B = [β, β, ..., β]
of ''k ''distinct elements of Ω is a base for G if the only element of G which fixes every β ∈ B pointwise is the identity element of G.
Bases and strong generating sets are concepts of importance in computational group theory. A base and a strong generating set (together often called a BSGS) for a group can be obtained using the Schreier–Sims algorithm.
It is often beneficial to deal with bases and strong generating sets as these may be easier to work with than the entire group. A group may have a small base compared to the set it acts on. In the "worst case", the symmetric groups and alternating groups have large bases (the symmetric group S has base size n − 1), and there are often specialized algorithms that deal with these cases.
In geometry, a base is a side of a polygon or a face of a polyhedron, particularly one oriented perpendicular to the direction in which height is measured, or on what is considered to be the "bottom" of the figure. This term is commonly applied to triangles, parallelograms, trapezoids, cylinders, cones, pyramids, parallelepipeds and frustums.
BASE (search engine)
BASE (Bielefeld Academic Search Engine) is a multi-disciplinary search engine to scholarly internet resources, created by Bielefeld University Library in Bielefeld, Germany. It is based on free and open-source software such as Apache Solr and VuFind. It harvests OAI metadata from institutional repositories and other academic digital libraries that implement the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH), and then normalizes and indexes the data for searching. In addition to OAI metadata, the library indexes selected web sites and local data collections, all of which can be searched via a single search interface.
Users can search bibliographic metadata including abstracts, if available. However, BASE does not currently offer full text search. It contrasts with commercial search engines in multiple ways, including in the types and kinds of resources it searches and the information it offers about the results it finds. Results can be narrowed down using drill down menus ( faceted search). Bibliographic data is provided in several formats, and the results may be sorted by multiple fields, such as by author or year of publication.
On 18 May 2016, BASE had indexed 93,161,843 documents from 4,352 content sources.
adj. serving as or forming a base; "the painter applied a base coat followed by two finishing coats" [syn: basal]
(used of metals) consisting of or alloyed with inferior metal; "base coins of aluminum"; "a base metal"
not adhering to ethical or moral principles; "base and unpatriotic motives"; "a base, degrading way of life"; "cheating is dishonorable"; "they considered colonialism immoral"; "unethical practices in handling public funds" [syn: dishonorable, dishonourable, immoral, unethical]
having or showing an ignoble lack of honor or morality; "that liberal obedience without which your army would be a base rabble"- Edmund Burke; "taking a mean advantage"; "chok'd with ambition of the meaner sort"- Shakespeare; "something essentially vulgar and meanspirited in politics" [syn: mean, meanspirited]
illegitimate [syn: baseborn]
debased; not genuine; "an attempt to eliminate the base coinage"
[also: bases (pl)]
n. any of various water-soluble compounds capable of turning litmus blue and reacting with an acid to form a salt and water; "bases include oxides and hydroxides of metals and ammonia" [syn: alkali]
installation from which a military force initiates operations; "the attack wiped out our forward bases" [syn: base of operations]
place that runner must touch before scoring; "he scrambled to get back to the bag" [syn: bag]
(numeration system) the positive integer that is equivalent to one in the next higher counting place; "10 is the radix of the decimal system" [syn: radix]
the bottom or lowest part; "the base of the mountain"
(anatomy) the part of an organ nearest its point of attachment; "the base of the skull"
a lower limit; "the government established a wage floor" [syn: floor]
the fundamental assumptions from which something is begun or developed or calculated or explained; "the whole argument rested on a basis of conjecture" [syn: basis, foundation, fundament, groundwork, cornerstone]
the bottom side of a geometric figure from which the altitude can be constructed; "the base of the triangle"
the most important or necessary part of something; "the basis of this drink is orange juice" [syn: basis]
the place where you are stationed and from which missions start and end [syn: home]
an intensely anti-western terrorist network that dispenses money and logistical support and training to a wide variety of radical Islamic terrorist group; has cells in more than 50 countries [syn: al-Qaeda, Qaeda, al-Qa'ida, al-Qaida]
the stock of basic facilities and capital equipment needed for the functioning of a country or area; "the industrial base of Japan" [syn: infrastructure]
the principal ingredient of a mixture; "glycerinated gelatin is used as a base for many ointments"; "he told the painter that he wanted a yellow base with just a hint of green"; "everything she cooked seemed to have rice as the base"
a flat bottom on which something is intended to sit; "a tub should sit on its own base"
(electronics) the part of a transistor that separates the emitter from the collector
[also: bases (pl)]
acr. '''''B'''uilding'', '''''A'''ntenna-tower'', '''''S'''pan'', '''''E'''arth'' alt. '''''B'''uilding'', '''''A'''ntenna-tower'', '''''S'''pan'', '''''E'''arth''
Douglas Harper's Etymology Dictionary
"bottom, foundation, pedestal," early 14c., from Old French bas "depth" (12c.), from Latin basis "foundation," from Greek basis "step, pedestal," from bainein "to step" (see come). The military sense is from 1860. The chemical sense (1810) was introduced in French 1754 by French chemist Guillaume-François Rouelle (1703-1770). Sporting sense of "starting point" ia from 1690s, also "destination of a runner" (1812). As a "safe" spot in a tag-like game, suggested from mid-15c. (as the name of the game later called prisoner's base).
late 14c., "low, of little height," from Old French bas "low, lowly, mean," from Late Latin bassus "thick, stumpy, low" (used only as a cognomen in classical Latin, humilis being there the usual word for "low in stature or position"), possibly from Oscan, or Celtic, or related to Greek basson, comparative of bathys "deep." Figurative sense of "low in the moral scale" is first attested 1530s in English, earlier "servile" (1520s). Base metals (c.1600) were worthless in contrast to noble or precious metals.
"to place on a foundation," 1841, from base (n.). Related: Based; basing.
The Collaborative International Dictionary
Bass \Bass\ (b[=a]s), n. [F. basse, fr. bas low. See Base, a.]
A bass, or deep, sound or tone.
The lowest part in a musical composition.
One who sings, or the instrument which plays, bass.
Thorough bass. See Thorough bass.
Usage examples of "base".
Not only was it exceptionally lofty, and on one flank of that series of bluffs which has before been mentioned as constituting the line upon which the Confederate grip of the stream was based, but the tortuous character of the channel gave particular facilities for an enfilading fire on vessels both before and after they came abreast the works.
Matter, then, thus brought to order must lose its own nature in the supreme degree unless its baseness is an accidental: if it is base in the sense of being baseness the Absolute, it could never participate in order, and, if evil in the sense of being Evil the Absolute, it could never participate in good.
From their bases first at Turin, and then at Coblenz, they were accused of planning invasions of France on the heels of absolutist armies that would put good patriots and their women and children to the sword and raze their cities.
Particle accelerators are based on the same principle: They hurl bits of matter such as electrons and protons at each other as well as at other targets, and elaborate detectors analyze the resulting spray of debris to determine the architecture of the objects involved.
Also, their Trident base in the state of Washington was included almost fifty percent more as an information addressee than in the preceding six months.
The limited informational content of DNAthe four bases adenine, guanine, cytosine, and thyminedid not seem adequate to build the fantastically varied amino acid necklaces.
She had used the base pairs of the DNA---combinations of pairs of four nucleotides called adenine, guanine, cytosine, and thy mine--to encode her message.
When that has been done, the burden rests on the regulated company to show that this item has neither been adequately covered in the rate base nor recouped from prior earnings of the business.
Further, admitting that there is an Intelligible Realm beyond, of which this world is an image, then, since this world-compound is based on Matter, there must be Matter there also.
Abu Obeidah admonished his brethren not to despise the baser origin of Dames, since he himself, could he relinquish the public care, would cheerfully serve under the banner of the slave.
Your choice to advertise on radio should be based upon the demographics of the station and the cost of drive-time commercials.
You may choose to advertise on certain cable companies based upon the demographics of their communities.
Most business owners -do not really understand that yellow page advertising is based upon the identical principles that apply to all creative messa i .
Argentine Base, Deception Island, disclosed that, on July 3, 16 persons including three Chilean sub officers had observed an aerial object over the northern area of the island moving in a north-northeast direction, varying speed, oscillatory course, changing yellow-green-orange color, leaving a contrail at 30 degrees elevation.
Still on the same day, at the Argentine base at Orkney Island, two meteorological observers sighted an aerial object flying at high speed on a parabolic trajectory, course E-W, white luminosity, causing disturbance in the magnetic field registered on geomagnetic instruments with patterns notably out of the normal.