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  • Achilles tendon (anatomy)
    strong tendon at the back of the heel that connects the calf muscles to the heel. The tendon is formed from the gastrocnemius and soleus muscles (the calf muscles) and is inserted into the heel bone. The contracting calf muscles lift the heel by this tendon, thus producing a foot action that is basic to walking, running, and jumping. The Achilles tendon is the thickest and most powerful tendon in ...
  • Achillini, Alessandro (Italian philosopher and physician)
    Italian philosopher and physician, an advocate of the teachings of William of Ockham....
  • Achin (province, Indonesia)
    semiautonomous province of Indonesia, forming the northern extremity of the island of Sumatra. Aceh is surrounded by water on three sides: the Indian Ocean to the west and north and the Strait of Malacca to the east. Its boundary with Sumatera Utara (North Sumatra) province to the southeast extends north-south from Salahaji on the northeaste...
  • Achinese (people)
    one of the main ethnic groups on the island of Sumatra, Indonesia. They were estimated to number roughly 2,100,000 in the late 20th century. They speak a language of the Austronesian (Malayo-Polynesian) family....
  • Achinese language
    ...languages include Cebuano, Tagalog, Ilokano, Hiligaynon, Bikol, Waray, Kapampangan, and Pangasinan of the Philippines; Malay, Javanese, Sundanese, Madurese, Minangkabau, the Batak languages, Acehnese, Balinese, and Buginese of western Indonesia; and Malagasy of Madagascar. Each of these languages has more than one million speakers. Javanese alone accounts for about one-quarter of all......
  • Achinese War (Southeast Asian history)
    (1873–1904), an armed conflict between The Netherlands and the Muslim sultanate of Acheh (now Aceh) in northern Sumatra that resulted in Dutch conquest of the Acehnese and, ultimately, in Dutch domination of the entire region. In 1871 The Netherlands and Britain had signed a treaty that recognized Dutch influence in northern Sumatra in return for Dutch ...
  • Achinsk (Russia)
    city, Krasnoyarsk kray (region), south-central Russia. It lies along the Chulym River, which is a tributary of the Ob. It was founded in 1621 and chartered in 1782. Important as a river-road transfer point until rail lines were constructed, it gained economic importance when an alumina plant was put into production in 1969 and when a petroleum refinery ...
  • Achinstein, Peter (philosopher)
    ...strategy began by questioning the Hempelian proposal that ordinary explanations consist in explanation sketches whose force derives from an unarticulated ideal explanation. Philosophers such as Peter Achinstein and Bas van Fraassen offered pragmatic theories, according to which what counts as an explanation is contextually determined. Their accounts remained close to the everyday practice......
  • Achitophel (biblical figure)
    in the Old Testament, one of King David’s most trusted advisers. He took a leading part in the revolt of David’s son Absalom, and Ahithophel’s defection was a severe blow to David. Having consulted Ahithophel about his plans to proceed against David, Absalom then sought advice from Hushai, another of David’s counselors. Hushai, who remained secretly l...
  • Achlya (fungus)
    ...in the other. In Allomyces (order Blastocladiales) a pheromone named sirenin, secreted by the female gametes, attracts the male gametes, which swim toward the former and fuse with them. In Achlya (phylum Oomycota, kingdom Chromista) a sterol pheromone called antheridiol induces the formation of gametangia and attracts the male to the female. In some simple fungi, which may have......
  • Achmed I (Ottoman sultan)
    Ottoman sultan from 1603 to 1617, whose authority was weakened by wars, rebellions, and misrule. The rebellions he was able to suppress; he executed some of the viziers and exiled many palace dignitaries for bribery and intrigue; and he introduced a new regulation for the improvement of land administration. The peace of Zsitvatörök (1606) that he signed with Austri...
  • Achmed II (Ottoman sultan)
    Ottoman sultan (1691–95) whose reign was marked by the continuing war with the Holy League (Austria-Poland-Venice)....
  • Achmed III (Ottoman sultan)
    sultan of the Ottoman Empire from 1703 to 1730....
  • Achmet I (Ottoman sultan)
    Ottoman sultan from 1603 to 1617, whose authority was weakened by wars, rebellions, and misrule. The rebellions he was able to suppress; he executed some of the viziers and exiled many palace dignitaries for bribery and intrigue; and he introduced a new regulation for the improvement of land administration. The peace of Zsitvatörök (1606) that he signed with Austri...
  • Achmet II (Ottoman sultan)
    Ottoman sultan (1691–95) whose reign was marked by the continuing war with the Holy League (Austria-Poland-Venice)....
  • Achmet III (Ottoman sultan)
    sultan of the Ottoman Empire from 1703 to 1730....
  • Acho, Mount (mountain, Ceuta, Spain)
    Gibraltar is considered one of the two Pillars of Heracles (Hercules), the other being Mount Hacho, on the African coast opposite. The Pillars, which according to Homer were created when Heracles broke the mountain that had connected Africa and Europe, defined the western limits of navigation for the ancient Mediterranean world. Since the 18th century Gibraltar has been a symbol of British......
  • Acholi (people)
    ethnolinguistic group of northern Uganda and southernmost Sudan. Numbering more than one million at the turn of the 21st century, they speak a Western Nilotic language of the Eastern Sudanic branch of the Nilo-Saharan family and are culturally and historically related to their traditional enemies, the neighbouring ...
  • achondrite (meteorite)
    any stony meteorite containing no chondrules (small, roughly spherical objects that formed in the solar nebula). The only exclusions are carbonaceous chondrites of the CI group, which, though they are clearly chondrites, are so heavily altered by water that any evidence for their having contained chondru...
  • achondroplasia (genetics)
    genetic disorder characterized by an abnormality in the conversion of cartilage into bone. As a consequence, bones that depend on cartilage models for development, particularly long bones such as the femur and humerus, cannot grow. Achondroplasia is the most common cause of dwarfism. In those afflicted w...
  • Achoris (king of Egypt)
    ...independence, 4th-century Egypt was characterized by continual internal struggle for the throne. After a long period of fighting in the delta, a 29th dynasty (399–380 bc) emerged at Mendes. Achoris (ruled 393–380 bc), its third and final ruler, was especially vigorous, and the prosperity of his reign is indicated by many monuments in Upper and Lower Egy...
  • Achras (plant genus)
    ...with high photosynthetic capacities that flush green but suffer high levels of insect damage, consequently lowering the trees’ lifetimes. At the other extreme are tree species such as Manilkara, almendro, and the suicide tree, characterized by slower growth and lower light requirements, with the capacity for extended persistence under low light conditions. Such trees tend...
  • Achras zapota (tree and fruit)
    (species Manilkara zapota, or Achras zapota), tropical evergreen tree of a genus of about 80 species in the family Sapotaceae and its distinctive fruit. Though of no great commercial importance in any part of the world, the sapodilla is much appreciated in many tropical and subtropical areas, where it is eaten fresh. The fruit is spheroid to ovoid in shape, rusty brown on the surface...
  • Achroia grisella (insect)
    The larvae of the lesser wax moth, Achroia grisella, cause damage to stored combs similar to that of the greater wax moth. The Mediterranean flour moth larva, Anagasta kuehniella, feeds on pollen in the combs and causes some damage. Control for both of these moths is the same as for the greater wax moth....
  • achroite (mineral)
    ...usually recognized: iron tourmaline (schorl), black in colour; magnesium tourmaline (dravite), brown; and alkali tourmaline, which may be pink (rubellite), green (Brazilian emerald), or colourless (achroite). Some crystals are pink at one end and green at the other; concentric colour zoning may also occur. The coloured varieties, when transparent and free from flaws, are cut as gems....
  • achromatic lens (optics)
    ...microscope languished for nearly 200 years, mainly because the early lenses tended to break up white light into its constituent parts. This technical problem was not solved until the invention of achromatic lenses, which were introduced about 1830. In 1878 a modern achromatic compound microscope was produced from the design of the German physicist Ernst Abbe. Abbe subsequently designed a......
  • achromatic point (optics)
    ...closed curve, as shown in the standard chromaticity diagram. Points along the circumference correspond to saturated colours; pale unsaturated colours appear closer to the centre of the diagram. The achromatic point is the central point at x = 13, y = 13 (shown as W in the figur...
  • Achromatium (bacteria)
    ...Some bacteria are relatively large, such as Azotobacter, which has diameters of 2 to 5 μm or more; the cyanobacterium Synechococcus, which averages 6 μm by 12 μm; and Achromatium, which has a minimum width of 5 μm and a maximum length of 100 μm, depending on the species. Giant bacteria can be visible with the unaided eye, such as Titano...
  • achromatopsia (ophthalmology)
    Acquired colour blindness is usually of the blue-yellow type and can be due to retinal diseases, glaucoma, or optic nerve diseases. Total colour blindness (achromatopsia) is an extremely rare congenital affliction that is typically associated with poor vision, nystagmus (rapid, uncontrollable eye movements), and light sensitivity....
  • Achterberg, Gerrit (Dutch poet)
    Dutch poet whose use of surreal language and imagery influenced a generation of post-World War II poets known as the Experimentalists. His verse, traditional in form, is characterized as romantic and metaphysical. He was a linguistic innovator, often coining new words based on the terminology of science and scholarship....
  • Achterhoek (region, The Netherlands)
    ...with sandy soil; south is fertile clay alluvium. The northern portion is divided by the broad valley (Gelderse) of the IJssel into the Veluwe (“Bad Land”) region on the west and the Achterhoek on the east. The hill plateau of the Veluwe is covered with scantily cultivated heaths and some woods, of primarily fir and beech. There are two national parks (Hoge Veluwe and Veluwezoom).....
  • “Achterhuis, Het” (work by Frank)
    Friends who had searched the family’s hiding place after their capture later gave Otto Frank the papers left behind by the Gestapo. Among them he found Anne’s diary, which was published as The Diary of a Young Girl (originally in Dutch, 1947). Precocious in style and insight, it traces her emotional growth amid adversity. In it she wrote, “In spite of everything I...
  • Achtung Baby (album by U2)
    U2 reinvented itself for the new decade, reemerging in 1991 with the album Achtung Baby and a sound heavily influenced by European experimental, electronic, and disco music. With this came a stage show that trafficked in irony and self-deprecating humour, qualities virtually absent from the band’s music in the previous decade; the 1992 Zoo TV tour was one of th...
  • “Achtung! Panzer!” (work by Guderian)
    ...interested in armoured warfare. Attracting Adolf Hitler’s attention in 1935, he rose rapidly and was able to put many of his revolutionary ideas into practice. His Achtung! Panzer! (1937; Attention! Tanks!) incorporated many of the theories of the British general J.F.C. Fuller and General Charles de Gaulle, who advocated the creation of independent armoured formations with ...
  • “Achtzehnte Brumaire des Louis Bonaparte, Der” (essay by Marx)
    ...conspiracy and wrote a pamphlet on their behalf. The same year he also published, in a German-American periodical, his essay “Der Achtzehnte Brumaire des Louis Napoleon” (The Eighteenth Brumaire of Louis Bonaparte), with its acute analysis of the formation of a bureaucratic absolutist state with the support of the peasant class. In other respects the next 12 years......
  • Achyuta Deva Rāya (Vijayanagar ruler)
    Krishna Deva had passed over his infant son and his young nephew and picked his half brother Achyuta Deva Raya (reigned 1529–42) to succeed him. Following a brief succession dispute, Achyuta Deva Raya was able to reach the capital from Chandragiri, where Krishna Deva had kept him and other princes confined, and to ascend the throne. Although he probably was not as dissolute a ruler as the.....
  • acicular texture (mineralogy)
    ...flat, platelike individuals arranged in layers; bladed, elongated crystals flattened like a knife blade; fibrous, an aggregate of slender fibres, parallel or radiating; acicular, slender, needlelike crystals; radiating, individuals forming starlike or circular groups; globular, radiating individuals forming small spherical or hemispherical groups;......
  • acid (chemical compound)
    any substance that in water solution tastes sour, changes the colour of certain indicators (e.g., reddens blue litmus paper), reacts with some metals (e.g., iron) to liberate hydrogen, reacts with bases to form salts, and promotes certain chemical reactions (acid catalysis). Examples of acids include the inorganic substances known as the mineral acids—sulfuric, nitric, hydroc...
  • acid anhydride (chemical compound)
    Esters have an alkoxy (OR) fragment attached to the acyl group; amides have attached amino groups (−NR2); acyl halides have an attached chlorine or bromine atom; and anhydrides have an attached carboxyl group. Each type of acid derivative has a set of characteristic reactions that qualifies it as a unique functional group, but all acid derivatives can be readily......
  • acid bite (art)
    The acid bite of the plate is a critical stage in the making of an etching. The printmaker must be familiar with the characteristics of the materials that are being used. On a zinc plate nitric acid is used. In the process of biting, this acid develops air bubbles over the bitten area. Under the bubbles the acid action is slower, and, therefore, if the bubbles are not constantly moved around by......
  • Acid Black 1 (dye)
    ...groups direct in weakly acidic media. H-acid (8-amino-1-naphthol-3,6-disulfonic acid) has both functional groups and can be selectively coupled to two diazo components in a two-step process. C.I. Acid Black 1 is formed by coupling first to diazotized p-nitroaniline in weakly acidic solution and then to diazotized aniline in alkaline solution....
  • acid chloride (chemical compound)
    Acyl halides...
  • acid dye (chemical compound)
    any bright-coloured synthetic organic compound whose molecule contains two groups of atoms—one acidic, such as a carboxylic group, and one colour-producing, such as an azo or nitro group. Acid dyes are usually applied in the form of their sodium salts, chiefly on wool but also on silk and, to a limited extent, in combination with a mordant, or fixing agent, on cotton and rayon. These dyest...
  • acid halide (chemical compound)
    neutral compound that reacts with water to produce an acid and a hydrogen halide. Acid halides are ordinarily derived from acids or their salts by replacement of hydroxyl groups by halogen atoms. The most important organic acid halides are the chlorides derived from carboxylic acids and from sulfonic acids. The carboxylic acid chlorides, called acyl halides, are generally more ...
  • acid house (music)
    ...such as Frankie Knuckles and Marshall Jefferson, house reached Europe by 1986, with tracks on Chicago labels Trax and DJ International penetrating the British pop charts. In 1988 the subgenre called acid house catalyzed a British youth culture explosion, when dancers discovered that the music’s psychedelic bass lines acted synergistically with the illegal drug ecstasy (MDMA, or......
  • acid hydrolase (enzyme)
    ...and microorganisms. Each lysosome is surrounded by a membrane that maintains an acidic environment within the interior via a proton pump. Lysosomes contain a wide variety of hydrolytic enzymes (acid hydrolases) that break down macromolecules such as nucleic acids, proteins, and polysaccharides. These enzymes are active only in the lysosome’s acidic interior; their acid-dependent activity...
  • acid indigestion
    When gastric contents, containing hydrochloric acid, flow backward from the stomach, the lining of the esophagus becomes inflamed, leading to the burning sensation known as heartburn. Occasional heartburn (also known as acid indigestion) is a common occurrence, typically precipitated by eating certain foods. However, some people experience heartburn regularly, a condition known as......
  • acid leaching (industrial process)
    Acid leaching is commonly performed by agitating an ore-leach mixture for 4 to as long as 48 hours at ambient temperature. Except in special circumstances, sulfuric acid is the leachant used; it is supplied in amounts sufficient to obtain a final leach liquor at about pH 1.5. Sulfuric acid leaching circuits commonly employ either manganese dioxide or chlorate ion to oxidize the tetravalent......
  • acid lead (alloy)
    ...for piping and as a lining material. Common lead is fully refined and desilvered lead, with low copper content; it is widely used wherever high corrosion resistance is not necessary. Acid lead, made by adding copper to fully refined lead, differs from chemical lead primarily in its higher bismuth content....
  • acid maltase deficiency (pathology)
    hereditary defect in the body’s ability to metabolize glycogen, resulting in a muscle disorder that is usually fatal during the first year of life. The defect responsible, absence of the enzyme alpha-1,4-glucosidase, is extremely rare, occurring in fewer than one in every 150,000 births, and is transmitted as an autosomal recessive trait. In Pompe’s disease, glycogen accumulates in a...
  • acid phosphatase (enzyme)
    ...usually shows elevated serum values in such conditions as Paget’s disease (inflammation of the bone) and osteomalacia (softening of the bone), as well as in hepatitis and obstructive jaundice; (4) acid phosphatase, an enzyme found in most body tissue but in unusually high concentration in the adult prostate gland; it is released into the circulation in metastatic cancer of the prostate; ...
  • acid rain (pollution)
    form of precipitation containing a heavy concentration of sulfuric and nitric acids. The term is also commonly applied to snow, sleet, and hail that manifest similar acidification. Such precipitation has become an increasingly serious environmental problem in many areas of North America, Europe, and Asia (see ). Although this form of ...
  • acid rock (igneous rock)
    division of igneous rocks on the basis of their silica content. Chemical analyses of the most abundant components in rocks usually are presented as oxides of the elements; igneous rocks typically consist of approximately 12 major oxides totaling over 99 percent of the rock. Of the oxides, silica (SiO2) is usually the most abundant...
  • acid–base catalysis (chemistry)
    acceleration of a chemical reaction by the addition of an acid or a base, the acid or base itself not being consumed in the reaction. The catalytic reaction may be acid-specific (acid catalysis), as in the case of decomposition of the sugar sucrose into glucose and fructose in sulfuric acid; or base-specific (base catalysis), as in the addition of hydrogen cyanide to aldehydes ...
  • acid-base equilibrium (chemical reaction)
    Certain general principles apply to any solvent with both acidic and basic properties—for example, water, alcohols, ammonia, amines, and acetic acid. Denoting the solvent molecule by SH, proton transfer can give rise to the ions SH2+ and S−, sometimes called lyonium and lyate ions, respectively (see above). In the pure solvent these are the only ions....
  • acid–base reaction (chemistry)
    a type of chemical process typified by the exchange of one or more hydrogen ions, H+, between species that may be neutral (molecules, such as water, H2O; or acetic acid, CH3CO2H) or electrically charged (ions, such as ammonium, NH4+; hydroxide, OH−; or carbonate, CO23...
  • acid-base theory (chemistry)
    ...
  • acid-base titration (chemical process)
    ...will signal the end point at, or very close to, the equivalence point. Such titrations, classified according to the nature of the chemical reaction occurring between the sample and titrant, include: acid-base titrations, precipitation titrations, complex-formation titrations, and oxidation-reduction (redox) titrations. In acid-base titration (i.e., the titration of an acid with a base, o...
  • acid-copper lead (alloy)
    ...for piping and as a lining material. Common lead is fully refined and desilvered lead, with low copper content; it is widely used wherever high corrosion resistance is not necessary. Acid lead, made by adding copper to fully refined lead, differs from chemical lead primarily in its higher bismuth content....
  • Acidalia Planitia (region, Mars)
    ...encompass all of the terrain within 30° of the pole except for the layered terrains immediately around the pole. Three broad lobes extend to lower latitudes. These include Chryse Planitia and Acidalia Planitia (centred on 30° W longitude), Amazonis Planitia (160° W), and Utopia Planitia (250° W). The only significant relief in this huge area is a large ancient impact...
  • acidity (chemistry)
    ...and the expressions in brackets are the concentrations of the respective substances. The hydrogen ion concentration of the buffer solution is dependent on the relative amounts of acetic acid and acetate ion (or sodium acetate) present, known as the buffer ratio. The addition of an acid or a base will cause corresponding changes in the concentration of acetic acid and acetate ion, but as long......
  • acidity exponent (chemistry)
    ...Since readily accessible values of Ka are always much less than unity, it is often convenient to introduce a quantity pKa, sometimes called the acidity exponent, and defined by the relation pKa = −log10Ka. Values of pKa are generally of a more convenient......
  • acidity function (chemistry)
    ...H9O4+), and a decrease in water content increases the proton-donating power of the solution. The acidity of these concentrated solutions is commonly measured by the acidity function, H0, a quantity measured by the effect of the solvent on a basic indicator I. It is defined by H0 + pKih+......
  • acidosis (pathology)
    abnormally high level of acidity, or low level of alkalinity, in the body fluids, including the blood. There are two primary types of acidosis: respiratory acidosis and metabolic acidosis. Respiratory acidosis results from inadequate excretion of carbon dioxide from the lungs. This may be caused by severe acute or chronic lung disease, such ...
  • acids and bases, proton theory of (chemistry)
    a theory, introduced independently in 1923 by the Danish chemist Johannes Nicolaus Brønsted and the English chemist Thomas Martin Lowry, stating that any compound that can transfer a proton to any other compound is an acid, and the compound that accepts the proton is a base. A proton is a nuclear particle with a unit positive electrical charge; it is represented by the sy...
  • acidulation (chemistry)
    Two principal techniques for converting phosphate rock to usable materials are practiced. One involves acidulation of the crushed rock—with either sulfuric or phosphoric acids—to form crude calcium hydrogen phosphates that, being water-soluble, are valuable additions to fertilizer. The other method is the reduction of the phosphate with carbon in an electric furnace to give......
  • Acier, Michel Victor (French sculptor)
    ...Sèvres, and the work of Meissen for the next 50 years is much less important than formerly. The transitional Louis XVI style of c. 1763–74 is typified by the figure modelling of Michel Victor Acier, who came to the factory to share the position of Modellmeister with Kändler in 1764. From 1774 to 1814 the Neoclassical style was increasingly used, and the design...
  • Acier Noir (typeface)
    ...cofounded the advertising agency Alliance Graphique and soon turned his attention to experimental typography. In 1929 he designed Bifur, a new typeface. Later, he designed two other typefaces, Acier Noir (1935) and Piegnot (1937). In 1939 he abandoned poster art and henceforth devoted himself to designing stage sets and to painting....
  • Aciéries Réunies de Burbach-Eich-Dudelange (Luxembourger company)
    integrated steelproducing company that is the largest industrial concern in Luxembourg....
  • Acilia Repetundarum, Lex (Roman law)
    ...tablet found in 1640 in Bruttium (the “toe” of Italy) and now in Vienna, is a consular edict on Senate authority, regulating Dionysiac outbursts in Italy in 186 bc; pieces of the laws Lex Acilia Repetundarum (123 bc) and Lex Agraria (111 bc) were found in the 16th century on opposite sides of what was once a large bronze tablet; the local ...
  • Acilius Glabrio (Roman consul)
    ...(Lex Oppia). Then, in an extensive and bitter military campaign, he stamped out an insurrection in Spain and organized the province of Nearer Spain. In 191 Cato served with distinction under Manius Acilius Glabrio at Thermopylae in the war against the Seleucid king Antiochus III. Shortly thereafter he included Glabrio in his denunciation of the supporters of the Scipios. He then attacked......
  • acinar cell (anatomy)
    ...to allow him use of a laboratory to search for the active substance from the pancreas. Banting guessed correctly that the islet cells secreted insulin, which was destroyed by enzymes from the acinar cells. By this time Banting had enlisted the support of Charles Best, a fourth-year medical student. Together they tied off the pancreatic ducts through which acinar cells release the......
  • Acinipo (Spain)
    town, Málaga provincia (province), in the Andalusia comunidad autónoma (autonomous community), southern Spain. It lies in the Ronda Mountains west of Málaga city. The town is situated on two hills divided by a deep ravine (...
  • Acinonyx (mammal)
    ...leopard, or ounce)1 Asian species.Subfamily AcinonychinaeGenus Acinonyx (cheetah)1 almost exclusively African......
  • Acinonyx jubatus (mammal)
    one of the world’s most recognizable cats, known especially for its speed. Cheetahs’ sprints have been measured at a maximum of 114 km (71 miles) per hour, and they routinely reach velocities of 80–100 km per hour while pursuing prey. Nearly all the cheetahs remaining in the wild live in Africa....
  • Ačinsk (Russia)
    city, Krasnoyarsk kray (region), south-central Russia. It lies along the Chulym River, which is a tributary of the Ob. It was founded in 1621 and chartered in 1782. Important as a river-road transfer point until rail lines were constructed, it gained economic importance when an alumina plant was put into production in 1969 and when a petroleum refinery ...
  • acinus (anatomy)
    ...trachea—there are about 650,000 terminal bronchioles. The cross-sectional area of the bronchial tree increases with increasing subdivision. The end of each terminal bronchiole opens into an acinus, so called because the structure resembles a cluster of grapes, and from this point onward the gas-exchanging portion of the lung is reached. The alveoli, or air sacs, which are divided into......
  • Acipenser (fish genus)
    ...trachea—there are about 650,000 terminal bronchioles. The cross-sectional area of the bronchial tree increases with increasing subdivision. The end of each terminal bronchiole opens into an acinus, so called because the structure resembles a cluster of grapes, and from this point onward the gas-exchanging portion of the lung is reached. The alveoli, or air sacs, which are divided into......
  • Acipenser fulvescens (fish)
    ...A smaller species, the sterlet (A. ruthenus), inhabits the Black and Caspian seas. A. stellatus occurs in rivers leading to the Black Sea, the Sea of Azov, and the Caspian Sea. The lake sturgeon of North America (A. fulvescens) occurs in the Mississippi valley, the Great Lakes, and northward into Canada. The white, Oregon, or Sacramento sturgeon (A. transmontanus)......
  • Acipenser guldenstadtii (fish)
    A. guldenstadtii is one of the most valuable species inhabiting the rivers of Russia and occurs eastward to Lake Baikal. It is about the same size as the common sturgeon and is found particularly in the rivers feeding the Black and Caspian seas. A smaller species, the sterlet (A. ruthenus), inhabits the Black and Caspian seas and is a valuable food fish about 0.9 m long.......
  • Acipenser huso (fish)
    large species of sturgeon....
  • Acipenser oxyrhynchus (fish)
    The common Old World sturgeon (Acipenser sturio) occurs from Scandinavia to the Mediterranean. A very similar, closely related form, considered a separate species (A. oxyrhynchus) by some authorities, occurs along the east coast of North America. The length of these fishes is generally to about 3 m; weight is to about 227 kg (500 pounds)....
  • Acipenser ruthenus (fish)
    ...is found along the east coast of North America from the St. Lawrence River to the Gulf of Mexico. A. gueldenstaedti occurs in western Russia east to Lake Baikal. A smaller species, the sterlet (A. ruthenus), inhabits the Black and Caspian seas. A. stellatus occurs in rivers leading to the Black Sea, the Sea of Azov, and the Caspian Sea. The lake sturgeon of North......
  • Acipenser stellatus (fish)
    ...in the rivers feeding the Black and Caspian seas. A smaller species, the sterlet (A. ruthenus), inhabits the Black and Caspian seas and is a valuable food fish about 0.9 m long. A. stellatus occurs in the rivers of the Black and Caspian seas and of the Sea of Azov. It has a long, pointed snout like the sterlet, and its flesh, caviar, and isinglass are highly valued....
  • Acipenser sturio (fish)
    The common Old World sturgeon (Acipenser sturio) occurs from Scandinavia to the Mediterranean. A very similar, closely related form, considered a separate species (A. oxyrhynchus) by some authorities, occurs along the east coast of North America. The length of these fishes is generally to about 3 m; weight is to about 227 kg (500 pounds)....
  • Acipenser transmontanus (fish)
    ...the Sea of Azov, and the Caspian Sea. The lake sturgeon of North America (A. fulvescens) occurs in the Mississippi valley, the Great Lakes, and northward into Canada. The white, Oregon, or Sacramento sturgeon (A. transmontanus) inhabits the waters of the Pacific Coast of North America from California to Alaska....
  • Acipenseridae (fish)
    any of about 25 species of fishes of the family Acipenseridae (subclass Chondrostei), native to temperate waters of the Northern Hemisphere. Most species live in the sea and ascend rivers (possibly once in several years) to spawn in spring or summer; a few others are confined to fresh water. Several species provide caviar from eggs....
  • Acipenseriformes (fish)
    The origin of the order Acipenseriformes (which includes the sturgeon) is not known, although they were clearly derived from some palaeonisciform groups. Fossils that are without doubt related to the sturgeons and paddlefishes are no older than the Upper Cretaceous (about 65,000,000 to 100,000,000 years ago). Earlier, the history of this order is poorly documented and confused. Both the......
  • Acireale (Italy)
    town and episcopal see, eastern Sicily, Italy, on terraces above the Ionian Sea at the foot of Mount Etna, 7 miles (11 km) northeast of Catania. Known as Aquilia by the Romans, the town was called Reale by Philip IV of Spain in 1642. The first part of its name is derived from the ancient Acis River, which according to legend welled forth at the death of the shepherd Acis, belove...
  • Acis (Greek mythology)
    in the Greek mythology of Ovid, the son of Faunus (Pan) and the nymph Symaethis. He was a beautiful shepherd of Sicily, the lover of the Nereid Galatea. His rival, Polyphemus the Cyclops, surprised them together and crushed him to pieces with a rock. His blood, gushing forth from beneath, was metamorphosed by Galatea into a river bearing his name, Acis or Acinius, at the base of...
  • Acis and Galatea (serenata by Handel)
    ...Scarlatti, George Frideric Handel, and most other composers of the late 17th and 18th centuries. One of the most enduring and well-known examples of this genre is Handel’s pastoral serenata Acis and Galatea (c. 1718)....
  • Acis et Galatée (ballet by Fokine)
    All the same, although at St. Petersburg he had no power to implement his beliefs, he began to work as a choreographer. His first ballet, created in 1905 for performance by his pupils, was Acis et Galatée, based on an ancient Sicilian legend. Fokine’s enthusiasm for antiquity owed nothing in origin to the “free dance” ideas of the American dancer Isadora Duncan,....
  • Acis in Oxford (work by Finch)
    ...of Toronto, to which he returned as a professor of French after three years in Paris. His first collection, Poems (1946), won a Governor General’s Award, as did a later work, Acis in Oxford (1961), a series of meditations inspired by a performance of G.F. Handel’s dramatic oratorio Acis and Galatea. Dover Be...
  • AcK (isotope)
    ...while studying actinium-227, which decays by negative beta decay (electron emission) to an isotope of thorium (thorium-227) and by alpha emission (about 1 percent) into an isotope of francium (francium-223) that was formerly called actinium K (AcK) and is a member of the actinium decay series. Though it is the longest-lived isotope of francium, francium-223 has a half-life of only 22......
  • “Ack libertas, tu ädla tingh” (work by Wivallius)
    ...mainly in prison, the best are those inspired by longing for freedom (for example, Ack libertas, tu ädla tingh, which was written about 1632 and translates as “Ah, Liberty, Thou Noble Thing”) and love of nature (most notably the majestic Klagovisa över denna torra och kalla vår [1642; “Dirge over This Dr...
  • ackee (plant)
    (Blighia sapida), tree of the soapberry family native to West Africa, widely cultivated throughout tropical and subtropical regions for its edible fruit. The tree grows about 9 metres (30 feet) tall and bears pinnate leaves and fragrant white flowers. Brought to the Caribbean area with slaves from Africa, the akee tree was introduced to science by William Bligh, famous as...
  • Acker, Kathy (American author)
    American novelist whose writing style and subject matter reflect the so-called punk sensibility that emerged in the 1970s....
  • Ackerley, J. R. (British writer and editor)
    British novelist, dramatist, poet, and magazine editor known for his eccentricity....
  • Ackerley, Joe Randolph (British writer and editor)
    British novelist, dramatist, poet, and magazine editor known for his eccentricity....
  • Ackerman, Diane (American author)
    American writer whose works often reflect her interest in natural science....
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