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  • ?iffīn, Battle of (Islamic history)

    Battle of ?iffīn, (May–July 657 ce), series of negotiations and skirmishes during the first Muslim civil war (fitnah; 656–661), ending in the arbitration of Adhru? (February 658–January 659), which undermined the authority of ?Alī as fourth caliph and prepared for the establishment of the Umayyad

  • Sifford, Charles Luther (American golfer)

    Charlie Sifford, (Charles Luther Sifford), American golfer (born June 2, 1922, Charlotte, N.C.—died Feb. 3, 2015, Cleveland, Ohio), became in 1960 the first nonwhite golfer to play in a PGA Tour event and was instrumental in forcing the PGA to formally end its 1934–61 Caucasians-only membership

  • Sifford, Charlie (American golfer)

    Charlie Sifford, (Charles Luther Sifford), American golfer (born June 2, 1922, Charlotte, N.C.—died Feb. 3, 2015, Cleveland, Ohio), became in 1960 the first nonwhite golfer to play in a PGA Tour event and was instrumental in forcing the PGA to formally end its 1934–61 Caucasians-only membership

  • Sífnos (island, Greece)

    Siphnus, Greek island of the Cyclades (Modern Greek: Kykládes) group, consisting of a limestone ridge whose principal peaks, Profíts Ilías (2,277 feet [694 metres]) and áyios Simeón (1,624 feet [495 metres]), are crowned by Byzantine churches. It constitutes a dímos (municipality) in the South

  • Sifra di-tzeni?uta (Jewish literature)

    Isaac ben Solomon Luria: …wrote a commentary on the Sifra di-tzeni?uta (“Book of Concealment”), a section of the Zohar. The commentary still shows the influence of classical Kabbala and contains nothing of what would later be called Lurianic Kabbala.

  • Sifré to Deuteronomy (biblical commentary)

    Sifré to Deuteronomy, systematic, verse by verse commentary to the book of Deuteronomy by the sages of Rabbinic Judaism. Since the Mishnah (c. 200 ce) and the Tosefta (c. 250 ce) are cited verbatim, a probable date for the work is c. 300 ce. Out of cases and examples, the sages sought

  • Sifré to Numbers (biblical commentary)

    Sifré to Numbers, commentary to the book of Numbers that dates to c. 300 ce and that provides a miscellaneous reading of most of that book. All authorities quoted in it enjoy the status of Mishnah sages, called tannaim (those who repeat oral traditions), and so the exegesis is called “tannaitic.”

  • Sig (Algeria)

    Sig, town, northwestern Algeria, on the Wadi Sig just below the confluence of the Wadi el-Mebto?h and the Wadi Matarah. To the north, the Sig plains stretch 20 miles (32 km) to the Gulf of Arzew, and to the southeast Mount Touakas rises to 1,145 feet (349 metres). The town has wide streets,

  • Sigalovada-sutta (Buddhist literature)

    Buddhism: Society and state: …on this topic is the Sigalovada-sutta, which has been called the “householder’s vinaya.”

  • Siganidae (fish)

    Rabbitfish, any of about 25 species of fishes constituting the family Siganidae (order Perciformes), found in shallow tropical marine waters from the Red Sea to Tahiti. They live in areas near shore or around reefs and graze on algae and other plants. Most rabbitfish are olive or brown in colour

  • Sigea, La (work by Coronado)

    Spanish literature: The Romantic movement: La Sigea (1854), the first of three historical novels, re-created the experience of the Renaissance humanist Luisa Sigea de Velasco; Jarilla and La rueda de desgracia (“The Wheel of Misfortune”) appeared in 1873. Poet, dramatist, and prose writer Gertrudis Gómez de Avellaneda was born in…

  • Sigebert (king of Wessex)

    Sigebert, king of the West Saxons, or Wessex (from 756), who succeeded his kinsman Cuthred and was himself overthrown by Cynewulf. Known for his corruption and cruelty, he soon faced a rebellion of his nobles and was formally deposed by the witan, which chose Cynewulf in his stead. After murdering

  • Sigebert (king of the East Angles)

    Sigebert, king of the East Angles. Before his reign Sigebert lived the life of an exile in Gaul, becoming Christianized and learned. He returned to an East Anglia troubled by anarchy and heathenism and became king in 630 or 631. Temporarily resigning his kingship (yielding it to his kinsman Ecgric)

  • Sigebert I (king of Essex)

    Sigebert I, king of the East Saxons, or Essex, who succeeded when his father and uncles were slain in battle with the West Saxons (c. 617). He probably reigned as a dependent of the West Saxon king Cynegils

  • Sigebert I (Merovingian king)

    Sigebert I, Frankish king of the Merovingian dynasty, son of Chlotar I and Ingund; he successfully pursued a civil war against his half brother, Chilperic I. When Chlotar I died in 561, his kingdom was divided, in accordance with Frankish custom, among his four sons; Sigebert became king of the

  • Sigebert II (king of Essex)

    Sigebert II, king of the East Saxons, or Essex (from c. 653), who succeeded Sigebert I. He became a Christian, was baptized (c. 653), and invited such missionaries as Saint Cedd into his land, which became a centre for their work. The date and occasion of Sigebert’s death are

  • Sigebert II (Merovingian king)

    Sigebert II, ephemeral successor to his father, Theodoric II, as king of Austrasia and Burgundy. Controlled by his great-grandmother Brunhild, he reigned only a matter of weeks before the hostility of the Austrasian nobility, led by Arnulf of Metz and Pippin I, to Brunhild led to his overthrow and

  • Sigebert III (Merovingian king)

    Sigebert III, one of the first so-called rois fainéants (“sluggard kings”) of the Merovingian dynasty, who held no real power of his own but was ruled by whoever was his mayor of the palace. Made king of Austrasia by his father, Dagobert I, in 634, the child Sigebert was governed first by his

  • Sigebert of Gembloux (French historian)

    Sigebert Of Gembloux, Benedictine monk and chronicler known for his Chronicon ab anno 381 ad 1113, a universal history widely used as a source by later medieval historians, and for his defense (1075) of Holy Roman Emperor Henry IV’s role in the Investiture Controversy, the struggle between emperors

  • Sigebert Parvus (king of Essex)

    Sigebert I, king of the East Saxons, or Essex, who succeeded when his father and uncles were slain in battle with the West Saxons (c. 617). He probably reigned as a dependent of the West Saxon king Cynegils

  • Sigebert Sanctus (king of Essex)

    Sigebert II, king of the East Saxons, or Essex (from c. 653), who succeeded Sigebert I. He became a Christian, was baptized (c. 653), and invited such missionaries as Saint Cedd into his land, which became a centre for their work. The date and occasion of Sigebert’s death are

  • Sigebert the Good (king of Essex)

    Sigebert II, king of the East Saxons, or Essex (from c. 653), who succeeded Sigebert I. He became a Christian, was baptized (c. 653), and invited such missionaries as Saint Cedd into his land, which became a centre for their work. The date and occasion of Sigebert’s death are

  • Sigebert the Little (king of Essex)

    Sigebert I, king of the East Saxons, or Essex, who succeeded when his father and uncles were slain in battle with the West Saxons (c. 617). He probably reigned as a dependent of the West Saxon king Cynegils

  • Sigel, Franz (American general)

    Battle of Wilson's Creek: Union General Franz Sigel attacked the rear of the Confederate forces with 1,200 men while Lyon led a frontal attack with the main Union force. Sigel was repulsed, and after several hours of fighting Lyon was killed. With casualties heavy on both sides, the Union forces retreated…

  • Sigeon (ancient city, Turkey)

    Peisistratus: Contribution to the growth of Athens: …end he secured command of Sigeum and installed a younger son, Hegesistratus, as its ruler. More important, he encouraged the Athenian Miltiades to lead a private venture that gained mastery over Chersonesus (near modern Sevastopol, Ukraine).

  • Siger de Brabant (Belgian philosopher)

    Siger de Brabant, professor of philosophy at the University of Paris and a leading representative of the school of radical, or heterodox, Aristotelianism, which arose in Paris when Latin translations of Greek and Arabic works in philosophy introduced new material to masters in the faculty of arts.

  • Siger of Brabant (Belgian philosopher)

    Siger de Brabant, professor of philosophy at the University of Paris and a leading representative of the school of radical, or heterodox, Aristotelianism, which arose in Paris when Latin translations of Greek and Arabic works in philosophy introduced new material to masters in the faculty of arts.

  • Sigerist, Henry Ernest (Swiss medical historian)

    Henry Ernest Sigerist, Swiss medical historian whose emphasis on social conditions affecting practice of the art brought a new dimension and level of excellence to his field. A graduate of the University of Zürich, Switz. (M.D. 1917), he succeeded the noted German physician Karl Sudhoff as director

  • Sigeum (ancient city, Turkey)

    Peisistratus: Contribution to the growth of Athens: …end he secured command of Sigeum and installed a younger son, Hegesistratus, as its ruler. More important, he encouraged the Athenian Miltiades to lead a private venture that gained mastery over Chersonesus (near modern Sevastopol, Ukraine).

  • Sighi?oara (Romania)

    Sighi?oara, town, Mure? jude? (county), central Romania. Situated in the historic region of Transylvania, it is 40 miles (65 km) northeast of Sibiu city and 110 miles (175 km) northwest of Bucharest. The town circles a hill, on the summit of which stands a citadel with a ring of walls, nine extant

  • Sighs, Bridge of (bridge, Venice, Italy)

    Bridge of Sighs, bridge in Venice, Italy, spanning the narrow canal (Rio di Palazzo) between the Doge’s Palace and the prisons. It was built about 1600 by the architect Antonio Contino. The enclosed passageway was so called from the “sighs” of the prisoners who passed over

  • sight (physiology)

    Vision, physiological process of distinguishing, usually by means of an organ such as the eye, the shapes and colours of objects. See eye;

  • sight hound (type of dog)

    dog: Hounds: There are scent hounds and sight hounds. They are a diverse group, ranging from the low-slung dachshund to the fleet-footed greyhound. However, they all are dedicated to the tasks for which they were bred, whether coursing over rough terrain in search of gazelles, such as the Afghan hound or the…

  • sight line (mathematics and art)

    projective geometry: …reality plane, RP) by so-called sight lines. The intersection of these sight lines with the vertical picture plane (PP) generates the drawing. Thus, the reality plane is projected onto the picture plane, hence the name projective geometry. See also geometry: Linear perspective.

  • sight method (reading technique)

    phonics: …challenged by proponents of “whole-language” instruction, a process in which children are introduced to whole words at a time, are taught using real literature rather than reading exercises, and are encouraged to keep journals in which “creative” spelling is permitted. A strong backlash against whole-language teaching polarized these two…

  • Sigillaria (Roman feast)

    Saturnalia: …the Saturnalia were known as Sigillaria, because of the custom of making, toward the end of the festival, presents of candles, wax models of fruit, and waxen statuettes which were fashioned by the sigillarii or manufacturers of small figures in wax and other media. The cult statue of Saturn himself,…

  • Sigillaria (fossil plant genus)

    Sigillaria, extinct genus of tree-sized lycopsids from the Carboniferous Period (about 360 to 300 million years ago) that are related to modern club mosses. Sigillaria had a single or sparsely branched trunk characterized by a slender strand of wood and thick bark. Long, thin leaves grew in a

  • sigillography

    Sigillography, the study of seals. A sealing is the impression made by the impact of a hard engraved surface on a softer material, such as clay or wax, once used to authenticate documents in the manner of a signature today; the word seal (Latin sigillum; old French scel) refers either to the matrix

  • SIGINT

    electronic warfare: …communications, which is known as signals intelligence (SIGINT) gathering. The purpose of jamming is to limit an enemy’s ability to exchange information by overriding radio transmissions or by sending signals to prevent radar detection or convey false information. Intelligence gathering has grown more significant in direct relation to the increased…

  • Sigiriya (historical site, Sri Lanka)

    Sigiriya, site in central Sri Lanka consisting of the ruins of an ancient stronghold that was built in the late 5th century ce on a remarkable monolithic rock pillar. The rock, which is so steep that its top overhangs the sides, rises to an elevation of 1,144 feet (349 metres) above sea level and

  • Sigismondo Malatesta Before Saint Sigismund (work by Piero della Francesca)

    Piero della Francesca: Formative period: …heraldic emblem in design) of Sigismondo Malatesta Before St. Sigismund in the Tempio Malatestiano, a memorial church built according to the architectural designs of Alberti. Also to this early formative period before 1451 belongs The Baptism of Christ. This painting, probably the central panel for an altarpiece for the Pieve…

  • Sigismund (Holy Roman emperor)

    Sigismund, Holy Roman emperor from 1433, king of Hungary from 1387, German king from 1411, king of Bohemia from 1419, and Lombard king from 1431. The last emperor of the House of Luxembourg, he participated in settling the Western Schism and the Hussite wars in Bohemia. Sigismund, a younger son of

  • Sigismund (king of Burgundy)

    France: The conquest of Burgundy: …moved into Burgundy, whose king, Sigismund, Theodoric’s son-in-law, had assassinated his own son. Sigismund was captured and killed. Godomer, the new Burgundian king, defeated the Franks at Vézeronce and forced them to retreat; Clodomir was killed in the battle. Childebert I, Chlotar I, and Theodebert I, the son of Theodoric…

  • Sigismund I (grand duke of Lithuania)

    Kyiv: Kyiv under Lithuania and Poland: …1516, when the grand duke Sigismund I granted Kyiv a charter of autonomy, thereby much stimulating trade.

  • Sigismund I (king of Poland)

    Sigismund I, king who established Polish suzerainty over Ducal Prussia (East Prussia) and incorporated the duchy of Mazovia into the Polish state. Sigismund I, the fifth son of Casimir IV and Elizabeth of Habsburg, had ruled G?ogów, Silesia, since 1499 and became margrave of Lusatia and governor of

  • Sigismund II Augustus (king of Poland)

    Sigismund II Augustus, last Jagiellon king of Poland, who united Livonia and the duchy of Lithuania with Poland, creating a greatly expanded and legally unified kingdom. The only son of Sigismund I the Old and Bona Sforza, Sigismund II was elected and crowned coruler with his father in 1530. He

  • Sigismund III Vasa (king of Poland and Sweden)

    Sigismund III Vasa, king of Poland (1587–1632) and of Sweden (1592–99) who sought to effect a permanent union of Poland and Sweden but instead created hostile relations and wars between the two states lasting until 1660. The elder son of King John III Vasa of Sweden and Catherine, daughter of

  • Sigismund of Tirol (Habsburg ruler)

    House of Habsburg: Austria and the rise of the Habsburgs in Germany: …Austrian hereditary lands reunited when Sigismund of Tirol abdicated in Maximilian’s favour (1490).

  • Sigismund the Old (king of Poland)

    Sigismund I, king who established Polish suzerainty over Ducal Prussia (East Prussia) and incorporated the duchy of Mazovia into the Polish state. Sigismund I, the fifth son of Casimir IV and Elizabeth of Habsburg, had ruled G?ogów, Silesia, since 1499 and became margrave of Lusatia and governor of

  • Sigismund Vasa (king of Poland and Sweden)

    Sigismund III Vasa, king of Poland (1587–1632) and of Sweden (1592–99) who sought to effect a permanent union of Poland and Sweden but instead created hostile relations and wars between the two states lasting until 1660. The elder son of King John III Vasa of Sweden and Catherine, daughter of

  • Sigismund, John (elector of Brandenburg)

    John Sigismund, elector of Brandenburg from 1608, who united his domain with that of Prussia. His marriage in 1594 to Anna, the daughter of Albert Frederick of Prussia, made him heir to the title of that duchy, and he became duke of Prussia in 1618. Through his mother-in-law he acquired rights o

  • sigla (symbols)

    biblical literature: Textual criticism: manuscript problems: …and of the utilization of sigla (signs or abbreviations) for marking suspect readings and disarranged verses. The Samaritan Pentateuch and the pre-Masoretic versions of the Old Testament made directly from Hebrew originals are all replete with divergences from current Masoretic Bibles. Finally, the scrolls from the Judaean desert, especially those…

  • siglo de las luces, El (work by Carpentier)

    Alejo Carpentier: …Carpentier published another historical novel, El siglo de las luces (Explosion in a Cathedral), which chronicles the impact of the French Revolution on Caribbean countries. It was very successful and there were calls to award Carpentier a Nobel Prize, something that eluded him. In his final years Carpentier turned to…

  • Siglo de Oro (Spanish literature)

    Golden Age, the period of Spanish literature extending from the early 16th century to the late 17th century, generally considered the high point in Spain’s literary history. The Golden Age began with the partial political unification of Spain about 1500. Its literature is characterized by p

  • siglos (ancient coin)

    coin: Achaemenids: …very pure quality and the siglos in silver; 20 sigloi (shekels) made a daric, which weighed 8.4 grams. The types of both coins were the same: obverse, the Persian king in a kneeling position holding a bow in his left hand and a spear in his right; reverse, only a…

  • sigma bond (chemistry)

    Sigma bond, in chemistry, a mechanism by which two atoms are held together as the result of the forces operating between them and a pair of electrons regarded as shared by them. In a sigma bond, the electron pair occupies an orbital—a region of space associated with a particular value of the

  • sigma compound (chemistry)

    Sigma bond, in chemistry, a mechanism by which two atoms are held together as the result of the forces operating between them and a pair of electrons regarded as shared by them. In a sigma bond, the electron pair occupies an orbital—a region of space associated with a particular value of the

  • sigma factor (biochemistry)

    metabolism: Synthesis of RNA: coli contains a protein, the sigma factor, that is not required for the incorporation of the nucleoside triphosphates into the growing RNA chain but apparently is essential for binding RNA polymerase to the proper DNA sites to initiate RNA synthesis. After the initiation step, the sigma factor is released; the…

  • Sigma Octantis (star)

    polestar: …pole; the present southern polestar, Polaris Australis (also called σ Octantis), is only of the 5th magnitude and is thus barely visible to the naked eye.

  • sigma orbital

    chemical bonding: Molecular orbitals of H2 and He2: …axis, it is designated a σ orbital and labeled 1σ.

  • sigma star orbital

    chemical bonding: Molecular orbitals of H2 and He2: …(and referred to as “sigma star”) or, because it is the second of the two σ orbitals, 2σ.

  • sigma-field (mathematics)

    probability theory: Measure theory: …properties (i)–(iii) is called a σ-field. From these properties one can prove others. For example, it follows at once from (i) and (ii) that ? (the empty set) belongs to the class M. Since the intersection of any class of sets can be expressed as the complement of the union…

  • sigma-t (unit of measurement)

    seawater: Density of seawater and pressure: …a density unit called sigma-t (σt). This value is obtained by subtracting 1.0 from the density and multiplying the remainder by 1,000. The σt has no units and is an abbreviated density of seawater controlled by salinity and temperature only. The σt of seawater increases with increasing salinity and…

  • Sigmodon (rodent)

    Cotton rat, (genus Sigmodon), any of 14 species of terrestrial rodents found from the southern United States to northern South America. Cotton rats are stout-bodied with small ears, and their coarse grizzled coats range from grayish brown to dark brown mixed with buff. All species live in natural

  • Sigmodon hispidus (rodent)

    hantavirus: …by the hispid cotton rat, Sigmodon hispidus); Louisiana, caused by the Bayou virus (carried by the marsh rice rat, Oryzomys palustris); Chile and Argentina, caused by the Andes virus (carried by Oligoryzomys longicaudatus, a species of pygmy rice rat); and Central America, caused by the Choclo

  • Sigmodontinae (rodent subfamily)

    grasshopper mouse: … species belong to the subfamily Sigmodontinae of the “true” mouse family, Muridae, within the order Rodentia. Today’s Onychomys species are related to grasshopper mice represented by four-million to five-million-year-old fossils that extend the evolutionary history of the genus back to the Early Pliocene Epoch (5.3 million to 3.6 million years…

  • sigmoid colon (anatomy)

    Sigmoid colon, a terminal section of the large intestine that connects the descending colon to the rectum; its function is to store fecal wastes until they are ready to leave the body. The sigmoid colon derives its name from the fact that it is curved in the form of an S (Greek sigma: σ). Its size

  • sigmoid colostomy (medicine)

    colostomy: A sigmoid colostomy, which is the most common type of permanent colostomy, requires no appliances (although a light pouch is sometimes worn for reassurance) and allows an individual to lead a life that is in every way normal except for the route of fecal evacuation.

  • sigmoidoscope (medical instrument)

    colorectal cancer: Diagnosis: …narrow, flexible tube called a sigmoidoscope to look at the lining of the rectum and the end of the colon. Colonoscopy uses a similar device to examine the entire colon. A biopsy may also be conducted in which abnormal tissue is removed by using the colonoscope and then examined under…

  • sigmoidoscopy (medicine)

    Sigmoidoscopy, diagnostic medical procedure that uses a flexible fibre-optic endoscope to examine the rectum and the terminal section of the large intestine, known as the sigmoid colon. Fifty percent of all lesions in the lower intestines occur specifically in the rectum and sigmoid colon; they can

  • Sigmund Freud on psychoanalysis

    The term psychoanalysis was not indexed in the Encyclop?dia Britannica until well into the 20th century. It occurs in the 12th edition (1922) in such articles as “Behaviorism” and “Psychotherapy.” The first treatment of psychoanalysis as a subject unto itself appeared in the 13th edition (1926),

  • Sigmurethra (gastropod order)

    gastropod: Classification: Order Sigmurethra Ureter originates near anterior margin of kidney, follows backward to posterior end, then reflexes forward along hindgut to open alongside anus; position greatly altered in sluglike forms; about 18,000 species. Suborder Holopodopes A group of 4 superfamilies. Superfamily Achatinacea

  • sign (advertising)

    Sign, in marketing and advertising, device placed on or before a premises to identify its occupant and the nature of the business done there or, placed at a distance, to advertise a business or its products. The ancient Egyptians and Greeks used signs for advertising purposes, as did the Romans,

  • sign (communications)

    communication: Signs: While signs are usually less germane to the development of words than signals, most of them contain greater amounts of meaning of and by themselves. Ashley Montagu, an anthropologist, has defined a sign as a “concrete denoter” possessing an inherent specific meaning, roughly analogous…

  • sign (medicine)

    human disease: Disease: signs and symptoms: Disease may be acute, chronic, malignant, or benign. Of these terms, chronic and acute have to do with the duration of a disease, malignant and benign with its potentiality for causing death.

  • Sign Forest (highway landmark, Yukon, Canada)

    Watson Lake: The “Sign Forest” at Milepost 634.3, just east of Watson Lake, is an unusual collection of signposts that originated in 1942 with homesick Alaska Highway construction workers who erected signs bearing the names of and distances to their hometowns; the practice was carried on by tourists…

  • Sign in Sidney Brustein’s Window, The (play by Hansberry)

    The Sign in Sidney Brustein’s Window, drama in three acts by Lorraine Hansberry, produced in 1964 and published the following year. The play concerns the nature of personal commitment to an ideal. The character Sidney Brustein is a disillusioned white Greenwich Village intellectual. Alton Scales, a

  • sign language (communications)

    Sign language, any means of communication through bodily movements, especially of the hands and arms, used when spoken communication is impossible or not desirable. The practice is probably older than speech. Sign language may be as coarsely expressed as mere grimaces, shrugs, or pointings; or it

  • sign learning (psychology)

    pedagogy: Conditioning and behaviourist theories: Such an event is called sign learning, because, in knowing the sign for something, people to some extent make a response to the sign similar to that which they would make to the object itself. Learning new vocabularies, new terms and conventions, or algebraic and chemical symbols all involve some…

  • Sign of the Cross, The (film by DeMille [1932])

    Claudette Colbert: DeMille’s The Sign of the Cross (1932). As Poppaea, the wife of Nero (played campily by Charles Laughton) and “the wickedest woman in the world,” Colbert slinked about in revealing costumes, vamped costar Fredric March, and in one famous scene took a bath in what was…

  • Sign of the Pagan (film by Sirk [1954])

    Douglas Sirk: Films of the early to mid-1950s: Sign of the Pagan (1954) was a florid tale of Rome under attack by Attila the Hun (Jack Palance), and Captain Lightfoot (1955) starred Hudson as a rebellious early 19th-century Irish nationalist.

  • Sign of the Ram, The (film by Sturges [1948])

    John Sturges: Early work: The melodrama The Sign of the Ram (1948) featured a wheelchair-bound Susan Peters (who had been crippled in a real-life accident) as a manipulative wife and mother who uses her condition to control those around her. In 1949 Sturges made the first of his many westerns, The…

  • Sign, Project (American UFO panel)

    unidentified flying object: Flying saucers and Project Blue Book: …investigation of these reports called Project Sign. The initial opinion of those involved with the project was that the UFOs were most likely sophisticated Soviet aircraft, although some researchers suggested that they might be spacecraft from other worlds, the so-called extraterrestrial hypothesis (ETH). Within a year, Project Sign was succeeded…

  • sign, road

    roads and highways: Traffic control: Signs advise the driver of special regulations and provide information about hazards and navigation. They are classified as regulatory signs, which provide notice of traffic laws and regulations (e.g., signs for speed limits and for stop, yield or give-way, and no entry); warning signs, which…

  • Signac, Paul (French painter)

    Paul Signac, French painter who, with Georges Seurat, developed the technique called pointillism. When he was 18, Signac gave up the study of architecture for painting and, through Armand Guillaumin, became a convert to the colouristic principles of Impressionism. In 1884 Signac helped found the

  • signal (communications)

    communication: Signals: A signal may be considered as an interruption in a field of constant energy transfer. An example is the dots and dashes that open and close the electromagnetic field of a telegraph circuit. Such interruptions do not require the construction of a man-made field;…

  • signal communication (communications)

    communication: Signals: A signal may be considered as an interruption in a field of constant energy transfer. An example is the dots and dashes that open and close the electromagnetic field of a telegraph circuit. Such interruptions do not require the construction of a man-made field;…

  • Signal Communication by Orbiting Relay Equipment (United States government project)

    aerospace industry: The space age: …1958, in a program called Project SCORE, the U.S. Air Force launched the first low-orbiting communications satellite, premiering the transmission of the human voice from space. Others followed, initiating a rapidly growing national and international telecommunications satellite industry (see satellite communication).

  • signal communications (communications)

    communication: Signals: A signal may be considered as an interruption in a field of constant energy transfer. An example is the dots and dashes that open and close the electromagnetic field of a telegraph circuit. Such interruptions do not require the construction of a man-made field;…

  • Signal Companies, Inc., The (American technology corporation)

    The Signal Companies, Inc., former American conglomerate corporation engaged mostly in automotive and aerospace engineering, energy development, and environmental improvement. It became part of AlliedSignal in 1985. The company was incorporated in 1928 as the Signal Oil and Gas Company to continue

  • Signal Corps (United States Army)

    Signal Corps, branch of the U.S. Army whose mission is to manage all aspects of communications and information systems support. The Signal Corps was officially established as a branch of the U.S. Army in March 1863. At the beginning of its involvement in the American Civil War, the Signal Corps

  • signal energy (sound)

    loudspeaker: …converting electrical energy into acoustical signal energy that is radiated into a room or open air. The term signal energy indicates that the electrical energy has a specific form, corresponding, for example, to speech, music, or any other signal in the range of audible frequencies (roughly 20 to 20,000 hertz).…

  • signal generator (electronics)

    Signal generator, electronic test instrument that delivers an accurately calibrated signal at frequencies from the audio to the microwave ranges. It is valuable in the development and testing of electronic hardware. The signal generator provides a signal that can be adjusted according to

  • Signal Hill (mountain, South Africa)

    Cape Town: The city site: … and Lion’s Rump (later called Signal Hill), on the north by Table Bay, on the south by Devil’s Peak, and on the east by marshlands and the sandy Cape Flats beyond. The nearest tillable land was on the lower eastern slopes of Devil’s Peak and Table Mountain and, farther to…

  • Signal Hill Historic Park (historical site, Saint John’s, Newfoundland, Newfoundland and Labrador, Canada)

    St. John's: Signal Hill Historic Park, once a location for signaling the approach of ships, memorializes several events, including John Cabot’s presumed landfall (commemorated by a tower [1897]); the French-English struggle for Newfoundland that ended in 1762 with the last shot fired on the hill (remnants of…

  • signal line (fishing)

    commercial fishing: Fish finding: Herring fishermen used signal lines to find their prey in deep waters. These were long wires dropped from a boat; the fisherman holding the line in his hand could feel the vibration caused by the fish touching the line, which was named the herring’s telephone. Other fish were…

  • signal processing (communications)

    radar: Signal and data processors: The signal processor is the part of the receiver that extracts the desired target signal from unwanted clutter. It is not unusual for these undesired reflections to be much larger than desired target echoes, in some cases more than one million times larger. Large clutter echoes…

  • signal recognition particle (molecule)

    cell: The rough endoplasmic reticulum: …RNA molecule known as the signal recognition particle (SRP). The SRP also binds to the ribosome to halt further formation of the protein. The membrane of the ER contains receptor sites that bind the SRP-ribosome complex to the RER membrane. Upon binding, translation resumes, with the SRP dissociating from the…

  • signal tower (military communications)

    Great Wall of China: Signal towers: Signal towers were also called beacons, beacon terraces, smoke mounds, mounds, or kiosks. They were used to send military communications: beacon (fires or lanterns) during the night or smoke signals in the daytime; other methods such as raising banners, beating clappers, or firing…

  • signal transduction (biochemistry)

    chemoreception: Cellular mechanisms in chemoreception: …cellular response is known as signal transduction.

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