• Sierra Pacaraima (mountains, South America)

    Pacaraima Mountains, central tabular upland of the Guiana Highlands in Brazil, Venezuela, and Guyana. The Pacaraima Mountains form the drainage divide between the Orinoco Valley to the north and the Amazon Basin to the south. Extending for 250 miles (400 km) in an east–west direction, the mountains

  • Sierra Parima (mountains, South America)

    Parima Mountains, range in northern Brazil and southern Venezuela. It is an outlying range of the Guiana Highlands and extends south-southeastward for about 200 miles (320 km), separating Venezuela from Brazil. Its peaks, largely unexplored, reach an elevation of 5,000 feet (1,500 metres) above sea

  • Sierra redwood (plant)

    giant sequoia, (Sequoiadendron giganteum), coniferous evergreen tree of the cypress family (Cupressaceae), the largest of all trees in bulk and the most massive non-clonal organism by volume. The giant sequoia is the only species of the genus Sequoiadendron and is distinct from the coast redwoods

  • Sierra San Pedro Mártir (mountain range, Mexico)

    Sierra San Pedro Mártir, mountain range in central Baja California state, northwestern Mexico. The range stretches southward about 90 miles (145 km) from southeast of Ensenada to San Fernando. Farther south the range becomes the Sierra de San Borja. The rugged, granitic mountains, forming the

  • Sierra Spanish (language)

    Ecuador: Languages of Ecuador: …between Sierra and Costa Spanish; Sierra Spanish has been influenced by Quichua. Quichua and Shuar (both of which are official intercultural languages) as well as other ancestral languages are spoken by the country’s Indigenous people. More than 10 Indigenous languages exist in Ecuador, and several of these will likely persist…

  • Sierra Vista (Arizona, United States)

    Sierra Vista, city, Cochise county, southeastern Arizona, U.S. Located 70 miles (113 km) southeast of Tucson, Sierra Vista is the county’s commercial and residential centre. At first a hamlet outside the gates of Fort Huachuca, a U.S. cavalry command post during the Apache Wars and later a

  • Sierra wave (air current)

    lee wave: …spectacular lee waves is the Sierra wave, which occurs when westerly winds flow over the Sierra Nevada Range in California. It is best developed when the polar-front jet stream blows across the range. In it, gliders have soared to elevations of more than 14,000 metres.

  • Sierra, Gregorio Martínez (Spanish dramatist)

    Gregorio Martínez Sierra was a poet and playwright whose dramatic works contributed significantly to the revival of the Spanish theatre. Martínez Sierra’s first volume of poetry, El poema del trabajo (1898; “The Poem of Work”), appeared when he was 17. Short stories reflecting the Modernist concern

  • Sierra, Justo (Mexican government official)

    científico: The learned Justo Sierra became minister of education and continued the educational reforms according to Positivist principles initiated in the 1870s by Gabino Barreda, a student of Comte and member of Benito Juárez’s government. In 1910 Sierra reopened the National University for the first time in almost…

  • Sierre (Switzerland)

    Alps: Geology: …in the Pennine Alps, and Sierre, Switzerland, look up to peaks that tower a mile and a half above them. In the valley of the Arve River near Mont Blanc, the difference in relief is more than 13,100 feet.

  • siesta (period of sleep)

    Spain: Organization of the day: …followed by a nap—the famous siesta—but, because most people now commute between home and work, this custom is in decline. Supper, a lighter meal, is also taken late, between 9:00 and 10:00 pm, or even later during the hot summer months.

  • Siete Ciudades de Cíbola, Las (legendary cities, North America)

    Seven Cities of Cíbola, legendary cities of splendour and riches sought in the 16th century by Spanish conquistadores in North America. The fabulous cities were first reported by Álvar Núñez Cabeza de Vaca who, after being shipwrecked off Florida in 1528, had wandered through what later became

  • siete colores (bird)

    tanager: An example is the paradise tanager (T. chilensis), called siete colores (Spanish) from its seven hues, including green, scarlet, and purple. The euphonias (Tanagra species) are found from Mexico southward; they should not be confused with Tangara species (above). Of the eight species of Thraupis, the blue, or blue-gray,…

  • Siete ensayos de interpretación de la realidad peruana (work by Maríategui)

    José Carlos Mariátegui: …de la realidad peruana (1928; Seven Interpretive Essays on Peruvian Reality). While emphasizing the economic aspects of Marxism, Mariátegui nonetheless does not repudiate the value of religion and myth in his treatment of the Indians. His views on literature, signaling the importance of indigenous themes and language while adhering to…

  • siete libros de la Diana, Los (work by Montemayor)

    The Two Gentlemen of Verona: …long Spanish prose romance titled Los siete libros de la Diana (1559?; The Seven Books of the Diana) by Jorge de Montemayor. Shakespeare is thought to have adapted the relationship of the two gentlemen of the title and the ending of the play from various possible sources, including Richard Edwards’s…

  • Siete Partidas, Las (Spanish code)

    Alfonso X: Siete partidas was the most important law code. It was based on Roman law and contained discourses on manners and morals and an idea of the king and his people as a corporation—superior to feudal arrangements—with the king as agent of both God and the…

  • Sieur de Monts National Park (national park, Maine, United States)

    Acadia National Park, national park on the Atlantic coast of Maine, U.S., astride Frenchman Bay. It has an area of 65 square miles (168 square km) and was originally established as Sieur de Monts National Monument (1916), named for Pierre du Guast, sieur (lord) de Monts. It became the first

  • sieva bean (plant, Phaseolus lunatus)

    lima bean, (Phaseolus lunatus), any of a variety of legumes (family Fabaceae) widely cultivated for their edible seeds. Of Central American origin, the lima bean is of commercial importance in few countries outside the Americas. There is a wide range of pod size and shape and of seed size, shape,

  • sieve area (plant anatomy)

    angiosperm: Organization of the vascular tissue: …the cell walls known as sieve areas, which have either small pores or large pores; the latter are known as sieve plates. Sieve plates are mostly located on the overlapping adjacent end walls. As sieve-tube members differentiate, they lose their nucleus, ribosomes, vacuoles, and dictyosomes (the equivalent of the Golgi…

  • sieve element (plant structure)

    sieve element, in vascular plants, elongated living cells of the phloem, the nuclei of which have fragmented and disappeared and the transverse end walls of which are pierced by sievelike groups of pores (sieve plates). They are the conduits of food (mostly sugar) transport from the leaves to the

  • sieve plate (plant anatomy)

    angiosperm: Organization of the vascular tissue: …the latter are known as sieve plates. Sieve plates are mostly located on the overlapping adjacent end walls. As sieve-tube members differentiate, they lose their nucleus, ribosomes, vacuoles, and dictyosomes (the equivalent of the Golgi apparatus in animals); they are not dead, however, and remain metabolically active. Each sieve-tube member…

  • sieve tray

    petroleum refining: Fractional distillation: Sieve trays are simple perforated plates with small holes about 5 to 6 mm (0.2 to 0.25 inch) in diameter. Valve trays are similar, except the perforations are covered by small metal disks that restrict the flow through the perforations under certain process conditions.

  • sieve-tube member (plant anatomy)

    angiosperm: Structural basis of transport: …consist of sieve cells and sieve-tube members, the latter differing in having some sieve areas specialized into sieve plates (generally on the end walls). Sieve-tube members are arranged end to end to form sieve tubes, a name derived from the sievelike end walls through which passage of food from one…

  • Sieveking, Amalie (German religious leader)

    Christianity: Care for the sick: In 1823 Amalie Sieveking developed a sisterhood analogous to the Daughters of Charity and was active in caring for the cholera victims of the great Hamburg epidemic of 1831. She was an inspiration to Theodor Fliedner, who founded the first Protestant hospital in Kaiserswerth in 1836 and…

  • Sievershausen, Battle of (German history)

    Wilhelm von Grumbach: …Franconia, until their defeat at Sievershausen the following year enabled the bishop of Würzburg to confiscate Grumbach’s lands. Grumbach obtained an order of restitution from the imperial court of justice, but he was unable to execute it, and in 1558 some of his followers assassinated the bishop. Grumbach fled to…

  • sievert (physics)

    sievert (Sv), unit of radiation absorption in the International System of Units (SI). The sievert takes into account the relative biological effectiveness (RBE) of ionizing radiation, since each form of such radiation—e.g., X-rays, gamma rays, neutrons—has a slightly different effect on living

  • Sievert, Hans (German athlete)

    decathlon: …of the United States, and Hans Sievert of Germany were leading competitors under the first table, with Sievert setting the final record of 8,790.46 points in 1934.

  • sieving (chemistry)

    separation and purification: Filtration and screening: In filtration, a porous material is used to separate particles of different sizes. If the pore sizes are highly uniform, separation can be fairly sensitive to the size of the particles, but the method is most commonly used to effect gross separations, as of…

  • Sieyès, Emmanuel-Joseph (French politician)

    Emmanuel-Joseph Sieyès was a churchman and constitutional theorist whose concept of popular sovereignty guided the National Assembly in its struggle against the monarchy and nobility during the opening months of the French Revolution. He later played a major role in organizing the coup d’état that

  • Sif (Norse goddess)

    Sif, goddess in Norse mythology known as the wife of the thunder god Thor. Her flaxen hair is thought to be connected to fertility and the harvest of grain. She is the mother of the god Ull (or Ullr), a deity of archery and skiing who is Thor’s stepson. Very little is said of Sif in the texts of

  • Sīf Allāh (Arab Muslim general)

    Khālid ibn al-Walīd was one of the two generals (with ʿAmr ibn al-ʿĀṣ) of the enormously successful Islamic expansion under the Prophet Muhammad and his immediate successors, Abū Bakr and ʿUmar. Although he fought against Muhammad at Uḥud (625), Khālid was later converted (627/629) and joined

  • Sif Mons (volcano, Venus)

    Venus: Volcanic features: Sif Mons is an example of such a volcano; there are more than 100 others distributed widely over the planet. Known as shield volcanoes, they reach heights of several kilometres above the surrounding plains and can be hundreds of kilometres across at their base. They…

  • sifaka (primate)

    sifaka, (genus Propithecus), any of nine species of leaping arboreal lemurs found in coastal forests of Madagascar. Sifakas are about 1 metre (3.3 feet) long, roughly half the length being tail. They have a small head, large eyes, and large ears that in most species are partially hidden in their

  • Sifakis, Joseph (French computer scientist)

    Joseph Sifakis is a Greek-born French computer scientist and cowinner of the 2007 A.M. Turing Award, the highest honour in computer science. Sifakis earned a bachelor’s degree (1969) in electrical engineering from the National Technical University of Athens and a master’s degree (1972) and a

  • Siferwas, John (British artist)

    Western painting: International Gothic: The style of John Siferwas, another painter active during this period, is similar, but his page decoration is usually more lavish; he produced a series of beautiful bird studies reminiscent of Lombard work. It should be noted, however, that this sort of realistic observation had long been a…

  • Ṣiffīn, Battle of (Islamic history)

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

  • 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-tzeniʿuta (Jewish literature)

    Isaac ben Solomon Luria: …wrote a commentary on the Sifra di-tzeniʿuta (“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-Mebtoûh 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 was the 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

  • Sigebert (king of the East Angles)

    Sigebert was the 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

  • Sigebert I (king of Essex)

    Sigebert I was the 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 was a 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

  • Sigebert II (king of Essex)

    Sigebert II was the 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 was the 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

  • Sigebert III (Merovingian king)

    Sigebert III was 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 was a 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

  • Sigebert Parvus (king of Essex)

    Sigebert I was the 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 was the 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 was the 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 was the 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 was a 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

  • Siger of Brabant (Belgian philosopher)

    Siger de Brabant was a 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

  • Sigerist, Henry Ernest (Swiss medical historian)

    Henry Ernest Sigerist was a 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, he succeeded the noted German physician Karl Sudhoff as director and professor

  • 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).

  • Sigh No More (album by Mumford & Sons)

    Mumford & Sons: …the band’s first studio album, Sigh No More, which contained that track, debuted at number 11 on British charts and climbed upward. Sigh No More was released in the United States in 2010 and was equally well received there. The album won the prize for British album of the year…

  • Sighișoara (Romania)

    Sighișoara, town, Mureș județ (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, enclosed limestone bridge in Venice, Italy, spanning the narrow canal (Rio di Palazzo) between the Doge’s Palace and the prisons. Commissioned by the doge Marino Grimani, whose familial coat of arms is depicted in the centre of the facade, the Baroque-style bridge was built about

  • 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 (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

  • 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,…

  • 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 (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 (Holy Roman emperor)

    Sigismund was the 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

  • Sigismund I (king of Poland)

    Sigismund I was a 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 Głogów, Silesia, since 1499 and became margrave of Lusatia and

  • 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 II Augustus (king of Poland)

    Sigismund II Augustus was the 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.

  • Sigismund III Vasa (king of Poland and Sweden)

    Sigismund III Vasa was the 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

  • 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 was a 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 Głogów, Silesia, since 1499 and became margrave of Lusatia and

  • Sigismund Vasa (king of Poland and Sweden)

    Sigismund III Vasa was the 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

  • Sigismund, John (elector of Brandenburg)

    John Sigismund was the 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

  • 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 patriotic

  • 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 energy

  • 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 energy

  • 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 Ø (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: Hantavirus pulmonary syndrome: …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…