ectopic pregnancy, condition in which the fertilized ovum (egg) has become imbedded outside the uterine cavity. The site of implantation most commonly is a fallopian tube; however, implantation can occur in the abdomen, the ovary, or the uterine cervix. Ectopic pregnancy occurs in an estimated 1 to

extravaganza, a literary or musical work marked by extreme freedom of style and structure and usually by elements of burlesque or parody, such as Samuel Butler’s Hudibras. The term extravaganza may also refer to an elaborate and spectacular theatrical production. The term once specifically referred

life-support system: …are the pressure suits and extravehicular activity (EVA) backpacks (i.e., portable systems that contain cooling fluid, oxygen flow and recirculation equipment, waste containment unit, power source, and communications apparatus) worn by astronauts when working outside of their spacecraft; the self-contained underwater breathing equipment (scuba gear) used by divers; and the…

introvert and extravert: extravert, basic personality types according to the theories of the 20th-century Swiss psychiatrist Carl Jung. According to these theories, an introvert is a person whose interest is generally directed inward toward his own feelings and thoughts, in contrast to an extravert, whose attention is directed…

extremum, in calculus, any point at which the value of a function is largest (a maximum) or smallest (a minimum). There are both absolute and relative (or local) maxima and minima. At a relative maximum the value of the function is larger than its value at immediately adjacent points, while at an

Extremadura, comunidad autónoma (autonomous community) and historical region of Spain encompassing the southwestern provincias (provinces) of Cáceres and Badajoz. Extremadura is bounded by the autonomous communities of Castile-León to the north, Castile–La Mancha to the east, and Andalusia to the

principles of physical science: Conservation of mass-energy: …is an example of an extremal principle—that a state of stable equilibrium is one in which the potential energy is a minimum with respect to any small changes in configuration. It may be regarded as a special case of one of the most fundamental of physical laws, the principle of…

golden ratio, in mathematics, the irrational number (1 + 5)/2, often denoted by the Greek letter ϕ or τ, which is approximately equal to 1.618. It is the ratio of a line segment cut into two pieces of different lengths such that the ratio of the whole segment to that of the longer segment is equal

Vince McMahon: …announced the creation of the Extreme Football League (XFL). While many questioned the move, citing the failure of past ventures to compete with the NFL, McMahon displayed his signature bravado and marketing muscle, slamming the NFL as dull and calling it the “No Fun League.” He promised a faster and…

extreme sports, sporting events or pursuits characterized by high speeds and high risk. The sports most commonly placed in this group are skateboarding, snowboarding, freestyle skiing, in-line roller-skating, street lugeing, and BMX and mountain biking. Typically, extreme sports operate outside

Television in the United States: Reality TV: …treatment on series such as Extreme Makeover (ABC, 2003–07), The Swan (Fox, 2004), and Queer Eye for the Straight Guy (Bravo, 2003–07).

David Cronenberg: Other work: …For (1995) and Michael Apted’s Extreme Measures (1996), and he played a reverend in the TV miniseries Alias Grace (2017), an adaptation of Margaret Atwood’s novel. In 2021 he appeared in season four of the anthology horror TV series Slasher, cast as a wealthy patriarch who makes his children compete…

obesity: Defining obesity: Morbid obesity (also known as extreme, or severe, obesity) is defined as a BMI of 40.0 or higher. (See nutritional disease: Diet and chronic disease.)

optimization: Basic ideas: …at a vertex, or “extreme point,” of the region. This will always be true for linear problems, although an optimal solution may not be unique. Thus, the solution of such problems reduces to finding which extreme point (or points) yields the largest value for the objective function.

Milky Way Galaxy: Principal population types: …to the very thin “extreme Population I” system. Each subdivision was found to contain (though not exclusively) characteristic types of stars, and it was even possible to divide some of the variable-star types into subgroups according to their population subdivision. The RR Lyrae variables of type ab, for example,…

Populations I and II: …as “extreme” Population I or II objects.

extreme sports, sporting events or pursuits characterized by high speeds and high risk. The sports most commonly placed in this group are skateboarding, snowboarding, freestyle skiing, in-line roller-skating, street lugeing, and BMX and mountain biking. Typically, extreme sports operate outside

rogue wave, a relatively unpredictable and unexpectedly high water wave arising at the water’s surface and formed from the coincidental stacking of multiple wind-driven wave crests passing through a single point or arising from a combination of waves and currents that may shorten the waves’

Extreme Ultraviolet Explorer (EUVE), U.S. satellite that operated from 1992 to 2001 and surveyed the sky for the first time in the extreme ultraviolet (EUV) region between 44 and 760 angstroms. (The extreme ultraviolet is defined to be between about 100 and 1,000 angstroms.) It had four telescopes

Solar Dynamics Observatory: …Imaging Assembly (AIA), and the Extreme Ultraviolet Variability Experiment (EVE). HMI studies changes in the Sun’s magnetic field by capturing images of the Sun in polarized light every 50 seconds. AIA observes the solar corona in eight wavelengths of ultraviolet light every 10 seconds. EVE determines every 10 seconds how…

anointing of the sick, in the Roman Catholic and Eastern Orthodox churches, the ritual anointing of the seriously ill and the frail elderly. The sacrament is administered to give strength and comfort to the ill and to mystically unite their suffering with that of Christ during his Passion and

tuberculosis: Diagnosis and treatment: …researchers reported the emergence of extremely drug-resistant tuberculosis (XXDR-TB), also known as totally drug-resistant tuberculosis (TDR-TB), in a small subset of Iranian patients. This form of the disease, which has also been detected in Italy (in 2003) and India (in 2011), is resistant to all first- and second-line antituberculosis drugs.

telecommunications media: The radio-frequency spectrum: …to extremely high frequency (EHF), ending at 300 gigahertz.

Stephen Daldry: In his next film, Extremely Loud & Incredibly Close (2011), based on a novel by American writer Jonathan Safran Foer, a precocious nine-year-old boy wanders around New York City in search of the lock to a key left behind by his father, who died in the September 11 attacks.

Stephen Daldry: …Close (2011), based on a novel by American writer Jonathan Safran Foer, a precocious nine-year-old boy wanders around New York City in search of the lock to a key left behind by his father, who died in the September 11 attacks.

electromagnetic radiation: Radio waves: Extremely low-frequency (ELF) waves are of interest for communications systems for submarines. The relatively weak absorption by seawater of electromagnetic radiation at low frequencies and the existence of prominent resonances of the natural cavity formed by Earth and the ionosphere make the range between 5…

nation-state: Religious extremism: The contemporary reinvigoration of religious extremism (which some scholars believe to be a counterreaction to globalization) poses two types of challenges to nation-states. First, within nation-states, religious extremists threaten interfaith coexistence, and they challenge the institutions that help to maintain ethnic, religious, and…

Farrah Fawcett: …as a rape survivor in Extremities (play, 1983; film,1986).

extremophile, an organism that is tolerant to environmental extremes and that has evolved to grow optimally under one or more of these extreme conditions, hence the suffix phile, meaning “one who loves.” Extremophilic organisms are primarily prokaryotic (archaea and bacteria), with few eukaryotic

extremophile, an organism that is tolerant to environmental extremes and that has evolved to grow optimally under one or more of these extreme conditions, hence the suffix phile, meaning “one who loves.” Extremophilic organisms are primarily prokaryotic (archaea and bacteria), with few eukaryotic

extremum, in calculus, any point at which the value of a function is largest (a maximum) or smallest (a minimum). There are both absolute and relative (or local) maxima and minima. At a relative maximum the value of the function is larger than its value at immediately adjacent points, while at an

respiratory disease: Asthma: …former condition is known as extrinsic asthma and the latter as intrinsic asthma. Extrinsic asthma commonly manifests first in childhood because the subject inherits an atopic characteristic: the serum contains specific antigens to pollens, mold spores, animal proteins of different kinds, and substances from a variety of insects, particularly cockroaches…

materials testing: Measurement of electrical properties: …from impurity atoms is called extrinsic.

motivation: Pull motives represent external goals that influence one’s behaviour toward them. Most motivational situations are in reality a combination of push and pull conditions. For example, hunger, in part, may be signaled by internal changes in blood glucose or fat stores, but motivation to eat…

coagulation: …of two separate pathways, designated extrinsic and intrinsic. Both pathways result in the production of factor X. The activation of this factor marks the beginning of the so-called common pathway of coagulation, which results in the formation of a clot.

apoptosis: Regulation of apoptosis: The extrinsic pathway is commonly associated with cellular death receptors.

cell membrane: One type, called the extrinsic proteins, is loosely attached by ionic bonds or calcium bridges to the electrically charged phosphoryl surface of the bilayer. They can also attach to the second type of protein, called the intrinsic proteins. The intrinsic proteins, as their name implies, are firmly embedded within…

industrial glass: Electronic conduction: In extrinsic semiconductivity, on the other hand, electrons are provided by defects in the chemical bonding and by impurity atoms. In oxide glasses containing transition-metal ions, for instance, it is believed that electronic conductivity occurs as the hopping of an electron between two transition-metal ions of…

extrinsicism, in philosophy or theology or both, the tendency to place major emphasis on external matters rather than on more profound realities. In terms of morals and ethics, it tends to stress the external observance of laws and precepts, with lesser concern for the ultimate principles

introvert and extravert: extravert, basic personality types according to the theories of the 20th-century Swiss psychiatrist Carl Jung. According to these theories, an introvert is a person whose interest is generally directed inward toward his own feelings and thoughts, in contrast to an extravert, whose attention is directed…

rubber: Shaping: Extruders are used to produce long continuous products such as tubing, tire treads, and wire coverings. They are also used to produce various profiles that can later be cut to length. Multiroll calenders are used to make wide sheeting. In transfer and injection molds, the…

extrusion, process in which metal or other material is forced through a series of dies to create desired shapes. Many ceramics are manufactured by extrusion, because the process allows efficient, continuous production. In a commercial screw-type extruder, a screw auger continuously forces the

papermaking: Finishing and converting: The extrusion-coating process, a relatively new development in the application of functional coating, has gained major importance in the past 20 years. The process is used to apply polyethylene plastic coatings to all grades of paper and paperboard. Polyethylene resin has ideal properties for use with…

extrusive rock, any rock derived from magma (molten silicate material) that was poured out or ejected at Earth’s surface. By contrast, intrusive rocks are formed from magma that was forced into older rocks at depth within Earth’s crust; the molten material then slowly solidifies below Earth’s

extrusive rock, any rock derived from magma (molten silicate material) that was poured out or ejected at Earth’s surface. By contrast, intrusive rocks are formed from magma that was forced into older rocks at depth within Earth’s crust; the molten material then slowly solidifies below Earth’s

protozoan: Mechanisms of food ingestion: …prey with special structures called extrusomes. Among the various types of extrusomes are the toxicysts, which are found in the oral region and release toxins that paralyze the prey.

inflammation: Vascular changes: Protein-rich fluid, called exudate, is now able to exit into the tissues. Substances in the exudate include clotting factors, which help prevent the spread of infectious agents throughout the body. Other proteins include antibodies that help destroy invading microorganisms.

angiosperm: Process of phloem transport: The phenomenon of exudation from injured sieve tubes supports the first possibility, which has been further supported by a discovery involving aphids (phloem-feeding insects): when aphids are removed from plants while feeding, their mouthparts remain embedded in the phloem. Exudate continues to flow through the mouthparts; the magnitude…

Easter: Liturgical observances: …of lights focused on the Paschal candle; the service of lessons called the prophecies; the administration of the sacraments of baptism and confirmation to adult converts; and the Easter mass. The use of the Paschal candle, to denote the appearance of light out of darkness through the Resurrection, was first…

Exuma Cays, group of some 365 cays and islands, part of The Bahamas, West Indies, situated in the Atlantic Ocean. The Exuma Cays begin some 35 miles (56 km) east-southeast of Nassau and stretch southeast in a gently curving arc for about 90 miles (145 km). Most of the inhabitants live on the

Exuma Cays: Exuma Cays Land and Sea Park, which includes many islands, islets, and cays and covers some 176 square miles (456 square km), was established in 1958 to preserve the many underwater reefs and uninhabited cays for exploration.

urban sprawl: Environmental costs: Exurban low-density neighbourhoods consume more energy per capita than their high-density counterparts closer to the city’s core. (An exurb is an affluent residential community located beyond the suburbs in a metropolitan area.) Energy for heating, cooking, cooling, lighting, and transportation is largely produced by burning…

dragonfly: Life cycle and reproduction: …behind a cast skin (exuvia).

Exxon Corporation, former oil and natural resources company that merged with Mobil Corporation as Exxon Mobil in 1999. The former Exxon company was founded in 1882 as part of the Standard Oil trust (see Standard Oil Company and Trust), which in 1899 became the holding company for all companies

Exxon Mobil Corporation, U.S.-based oil and gas company formed in 1999 through the merger of Exxon Corporation and Mobil Corporation. As one of the world’s top three oil and energy concerns, it has investments and operations in petroleum and natural gas, coal, nuclear fuels, chemicals, and mineral

oil spill: Largest oil-tanker spills in history: In North America the Exxon Valdez oil spill of 1989 in Prince William Sound, Alaska, caused great ecological and economic damage, though it ranks well below the largest oil-tanker spills in history if measured by the amount of oil spilled (37,000 metric tons).

Exxon Valdez oil spill, massive oil spill that occurred on March 24, 1989, in Prince William Sound, an inlet in the Gulf of Alaska, Alaska, U.S. The incident happened after an Exxon Corporation tanker, the Exxon Valdez, ran aground on Bligh Reef during a voyage from Valdez, Alaska, to California.

Exxon Mobil Corporation, U.S.-based oil and gas company formed in 1999 through the merger of Exxon Corporation and Mobil Corporation. As one of the world’s top three oil and energy concerns, it has investments and operations in petroleum and natural gas, coal, nuclear fuels, chemicals, and mineral

Gnassingbé Eyadéma was a soldier who became president of Togo after a military takeover in January 1967. Eyadéma joined the French army in 1953, served in Indochina, Dahomey, Niger, and Algeria (1953–61), and had attained the rank of sergeant when he returned to Togo in 1962. When President

Gnassingbé Eyadéma was a soldier who became president of Togo after a military takeover in January 1967. Eyadéma joined the French army in 1953, served in Indochina, Dahomey, Niger, and Algeria (1953–61), and had attained the rank of sergeant when he returned to Togo in 1962. When President

Bosnia and Herzegovina: Ottoman Bosnia: …the full status of an eyalet, or constituent province of the empire. Bosnia enjoyed this status as a distinct entity throughout the rest of the Ottoman period. The Bosnian eyalet was governed by a vizier and administered through a network of junior pashas and local judges. Land was distributed according…

falconry: Terms and equipment: …captivity is known as an eyas. A hawk trapped during its first year in the wild is called a passager, and a hawk trapped in its adult plumage is termed a haggard. The female peregrine falcon is properly called a falcon, and the male—which, in common with most species of…

Lake Eyasi, lake, northern Tanzania. It lies west of Lake Manyara and approximately 95 miles (155 km) southwest of Arusha. At an elevation of about 3,400 feet (1,040 m), the lake covers an area of about 400 square miles (1,050 square km) and occupies the bottom of a bowllike depression in a region

South African literature: In Afrikaans: …poet of the 1930s was Elisabeth Eybers, whose verse dealt initially with the intimate confessions of women but broadened out to a penetrating, objective approach to love, exile, old age, and the poetical craft. Besides writing vivid romantic poetry, Uys Krige was also a short-story writer and playwright and a…

Jonathan Eybeschütz was a rabbi and religious scholar noted for his bitter quarrel with Rabbi Jacob Emden, a dispute that split European Jewry and ended the effectiveness of rabbinic excommunication during Eybeschütz’s time. As a rabbi in a number of European towns, Eybeschütz became a celebrated

Ghent Altarpiece: …van Eyck and his brother Hubert van Eyck and was completed in 1432. It has been called “the first major oil painting” and is regarded as marking the transition from the Middle Ages to the Renaissance.

Jan van Eyck was a Netherlandish painter who perfected the newly developed technique of oil painting. His naturalistic panel paintings, mostly portraits and religious subjects, made extensive use of disguised religious symbols. His masterpiece is the altarpiece in the cathedral at Ghent, The

tropical cyclone: The eye: A characteristic feature of tropical cyclones is the eye, a central region of clear skies, warm temperatures, and low atmospheric pressure. Typically, atmospheric pressure at the surface of Earth is about 1,000 millibars. At the centre of a tropical cyclone, however, it is typically…

amphibian: Common features: The eye of the modern amphibian (or lissamphibian) has a lid, associated glands, and ducts. It also has muscles that allow its accommodation within or on top of the head, depth perception, and true colour vision. These adaptations are regarded as the first evolutionary improvements in…

eye colour, heritable phenotypic (observable) trait determined by pigmentation and light scattering in the iris of the eye. The iris, the coloured part of the eye, is the ring of muscle and collagen fibres around the central black opening of the eye known as the pupil, through which light passes.

eye dialect, the use of misspellings that are based on standard pronunciations (such as sez for says or kow for cow) but are usually intended to suggest a speaker’s illiteracy or his use of generally nonstandard pronunciations. It is sometimes used in literature for comic

eye disease, any of the diseases or disorders that affect the human eye. This article briefly describes the more common diseases of the eye and its associated structures, the methods used in examination and diagnosis, and the factors that determine treatment and prognosis. The first part deals with

John Schlesinger: Films of the 1990s and final work: …films were the intense drama Eye for an Eye (1996), about a revenge-driven mother (Sally Field) whose daughter was the victim of rape, and The Next Best Thing (2000), in which Madonna played a yoga instructor who decides to have a baby with her gay best friend (Rupert Everett).

eye for an eye, in law and custom, the principle of retaliation for injuries or damages. In ancient Babylonian, biblical, Roman, and Islāmic law, it was a principle operative in private and familial settlements, intended to limit retaliation, and often satisfied by a money payment or other

Denys Arcand: …Règne de la beauté (2014; An Eye for Beauty), about a married architect who has an affair; and La Chute de l’empire américain (2018; The Fall of the American Empire), a satiric crime thriller that explores greed in modern society.

frit fly, any small fly of the family Chloropidae (order Diptera), destructive to oats, rye, barley, wheat, and other cereal grains. Frit flies, often bright yellow and black, are usually found in grassy areas. The larvae are maggots and live in developing grain heads and within stems, causing the

Helen Mirren: Later films: Eye in the Sky (2015) featured Mirren as a British colonel who faces a moral dilemma while remotely commanding a military operation in Kenya intended to apprehend a terrorist.

microscope: Principles: …are generally referred to as eye loupes or jewelers’ lenses. The traditional simple microscope was made with a single magnifying lens, which was often of sufficient optical quality to allow the study of microscopical organisms including Hydra and protists.

photoreception: Eye movements and active vision: There are four main types of eye movement: saccades, reflex stabilizing movements, pursuit movements, and vergence movements. Saccades are fast movements that redirect gaze. They may involve the eyes alone or, more commonly, the eyes and the head. Their function…

eye movement and desensitization reprocessing therapy (EMDR), psychotherapy technique using visual bilateral stimulation—such as watching a light or an object move in a rhythmic pattern that triggers activity in both sides of the brain—to reduce distress associated with traumatic memories and life

Eye of Horus, in ancient Egypt, symbol representing protection, health, and restoration. According to Egyptian myth, Horus lost his left eye in a struggle with Seth. The eye was magically restored by Hathor, and this restoration came to symbolize the process of making whole and healing. For this

Kuruman: …known for a local spring—the Eye of Kuruman—which rises in a cave in this otherwise semidesert thornveld area and supplies at least 4,500,000 gallons (17,000,000 l) daily. Kuruman is also known for its dairy cattle and trade in butter. Pop. (2001) 9,823.

k.d. lang: …the films Salmonberries (1991) and Eye of the Beholder (1999). She also made guest appearances on the TV shows Ellen and Portlandia in 1997 and 2014, respectively.

Fleur Adcock: Adcock’s first collection of poetry, The Eye of the Hurricane, appeared the following year. In that and subsequent volumes—including Tigers (1967), High Tide in the Garden (1971), The Incident Book (1986), Time Zones (1991), and Looking Back (1997)—Adcock brought a measured, Classical

Donald Sutherland: …Nazi spy in the thriller Eye of the Needle (1981). Another classic dramatic role for Sutherland was as the tormented father in the Academy Award-winning film Ordinary People (1980). He played other paternal or avuncular film roles in A Dry White Season (1989), Cold Mountain (2003), The Italian

Eudora Welty: …collections of short stories, and The Eye of the Story (1978) is a volume of essays. The Collected Stories of Eudora Welty was published in 1980.

eye rhyme, in poetry, an imperfect rhyme in which two words are spelled similarly but pronounced differently (such as move and love, bough and though, come and home, and laughter and daughter). Some of these (such as flood and brood) are referred to as historical rhymes because at one time they

cosmetic: Eye makeup: …mascara to emphasize the eyelashes; eye shadow for the eyelids, available in many shades; and eyebrow pencils and eyeliner to pick out the edges of the lids. Because eye cosmetics are used adjacent to a very sensitive area, innocuity of ingredients is essential.

splice: …in a single rope, the eye splice, in which the free end is unlayed and interwoven at some point in the standing part of the rope, is employed, especially on sailing vessels.

Tall Birāk: …discoveries at Birāk was the Eye Temple (c. 3000), so named because of the thousands of small stone “eye idols” found there. These curious objects have almost square bodies and thin heads carved with two to six large eyes. The temple itself is important for its use of typically southern…

canine tooth, in mammals, any of the single-cusped (pointed), usually single-rooted teeth adapted for tearing food, and occurring behind or beside the incisors (front teeth). Often the largest teeth in the mouth, the canines project beyond the level of the other teeth and may interlock when the

eye worm, (species Loa loa), common parasite of humans and other primates in central and western Africa, a member of the phylum Nematoda. It is transmitted to humans by the deerfly, Chrysops (the intermediate host), which feeds on primate blood. When the fly alights on a human victim, the worm

human eye, in humans, specialized sense organ capable of receiving visual images, which are then carried to the brain. The eye is protected from mechanical injury by being enclosed in a socket, or orbit, which is made up of portions of several of the bones of the skull to form a four-sided pyramid,

eyeball, spheroidal structure containing sense receptors for vision, found in all vertebrates and constructed much like a simple camera. The eyeball houses the retina—an extremely metabolically active layer of nerve tissue made up of millions of light receptors (photoreceptors)—and all of the

bridge: Suspension bridges: …reinforced concrete with embedded steel eyebars to which the cables will be fastened. An eyebar is a length of metal with a hole (or “eye”) at the ends. Cables for the first suspension bridges were made of linked wrought-iron eyebars; now, however, cables are generally made of thousands of steel…

folly, (from French folie, “foolishness”), also called Eyecatcher, in architecture, a costly, generally nonfunctional building that was erected to enhance a natural landscape. Follies first gained popularity in England, and they were particularly in vogue during the 18th and early 19th centuries,

click beetle: The eyed elator (Alaus oculatus), a North American click beetle, grows to 45 mm (over 1.75 inches) long and has two large black-and-white eyelike spots on the prothorax, a region behind the head. The genus Pyrophorus, which occurs in the tropical areas of the Western Hemisphere,…

eyeglasses, lenses set in frames for wearing in front of the eyes to aid vision or to correct such defects of vision as myopia, hyperopia, and astigmatism. In 1268 Roger Bacon made the earliest recorded comment on the use of lenses for optical purposes, but magnifying lenses inserted in frames were

camel: Natural history: Heavy eyelashes protect the eyes from blowing sand, and the nostrils can be squeezed shut. The dromedary has horny pads on the chest and knees that protect it from searing desert sand when it lies down, but the Bactrian camel lacks these callosities. Camels are generally…

Eyeless in Gaza, novel of ideas by Aldous Huxley, published in 1936. This semiautobiographical novel criticizes the dearth of spiritual values in contemporary society. In nonchronological fashion the novel covers more than 30 years in the lives of a group of upper-middle-class English friends,