enamel, in anatomy, the hardest tissue of the body, covering part or all of the crown of the tooth in mammals. Enamel, when mature, consists predominantly of apatite crystals containing calcium and phosphate. Enamel is not living and contains no nerves. The thickness and density of enamel vary over

art conservation and restoration: Glass and other vitreous materials: Glass, glaze, enamel, and faience—the four vitreous products—are manufactured from three basic components: silica, alkali, and small amounts of calcium. Glass, glazes, and enamel (but not faience) contain high amounts of alkali, such as sodium oxide (soda glass) or potassium oxide (potash glass).

Chinese pottery: Song dynasty: The earliest known example of overglaze painting in the history of Chinese pottery bears a date equivalent to 1201. The technique was more widely used for the decoration of Cizhou wares in the 14th century. In both the variety and the vigour of their forms and decoration, Cizhou stonewares present…

enamel miniature, portrait on a small opaque, usually white, enamel surface annealed to gold or copper plate and painted with metallic oxides. Since the pigments used are not vitreous enamels, this is not a true enamelling process. The metallic paints are slightly fused to the enamel surface

tooth germ: Enamel organs, in the form of rounded swellings, develop in the dental lamina; each swelling is the future site of a single tooth. The enamel organ is responsible for mapping out the full size and shape of the crown of the tooth; it also exerts…

enamelwork, technique of decoration whereby metal objects or surfaces are given a vitreous glaze that is fused onto the surface by intense heat to create a brilliantly coloured decorative effect. It is an art form noted for its brilliant, glossy surface, which is hard and long-lasting. Enamels have

glassware: The Roman Empire: …specialties attributed to Alexandria were enamel painting (pigments mixed with a glassy flux were fused to the surface of the glass vessel by a separate firing) and an extraordinary technique of sandwiching a gold leaf etched with a design between two layers of clear glass.

enamelwork, technique of decoration whereby metal objects or surfaces are given a vitreous glaze that is fused onto the surface by intense heat to create a brilliantly coloured decorative effect. It is an art form noted for its brilliant, glossy surface, which is hard and long-lasting. Enamels have

porcelain enamelling, process of fusing a thin layer of glass to a metal object to prevent corrosion and enhance its beauty. Porcelain-enamelled iron is used extensively for such articles as kitchen pots and pans, bathtubs, refrigerators, chemical and food tanks, and equipment for meat markets. In

enamelwork, technique of decoration whereby metal objects or surfaces are given a vitreous glaze that is fused onto the surface by intense heat to create a brilliantly coloured decorative effect. It is an art form noted for its brilliant, glossy surface, which is hard and long-lasting. Enamels have

amine: Oxidation: …amines can be oxidized to enamines (R2C=CHNR2) by a variety of reagents.

Spanish literature: Medieval poetry: Macías El Enamorado (flourished mid-14th century) was the last Galician troubadour; Galicians thereafter wrote in Castilian, and, though there were echoes of their tradition, the Renaissance and Castilian political hegemony finally ended Galician literature until the 19th century.

Magnoliales: Timber: Enantia chlorantha (African whitewood), a yellowwood from Liberia, Ivory Coast, and Cameroon, produces a sulfurous yellow dye; the wood also is used locally to make unpainted furniture and veneers. Cleistopholis patens (otu) yields a soft, light wood from western Africa that finds some of the same uses…

enantiomer, either of a pair of objects related to each other as the right hand is to the left—that is, as mirror images that cannot be reoriented so as to appear identical. An object that has a plane of symmetry cannot be an enantiomer because the object and its mirror image are identical.

enantiomer, either of a pair of objects related to each other as the right hand is to the left—that is, as mirror images that cannot be reoriented so as to appear identical. An object that has a plane of symmetry cannot be an enantiomer because the object and its mirror image are identical.

crustacean: Annotated classification: †Order Enantiopoda Carboniferous; single fossil, Tesnusocaris. Class Maxillopoda Five pairs of head appendages; single, simple, median eye; antennules uniramous; maxillae usually present; up to 11 trunk segments; over 23,000 species. Subclass Thecostraca

allotropy: …stable under all conditions, or enantiotropic, in which case different forms are stable under different conditions and undergo reversible transitions from one to another at characteristic temperatures and pressures.

enarean, member of an ancient group of magicians and soothsayers, most likely eunuchs, who spoke in high-pitched voices and dressed as women. All that is known of them appears in the writings of the ancient Greek historian Herodotus (flourished 5th century bce). They claimed that a goddess,

enargite, sulfosalt mineral, copper arsenic sulfide (Cu3AsS4), that is occasionally an important ore of copper. It occurs as heavy, metallic-gray crystals and masses in veins and replacement deposits. Economically valuable deposits have been found in the Balkans; at several places in Peru;

St. Augustine: Sermons: …collection, Enarrationes in Psalmos (392–418; Enarrations on the Psalms). These are perhaps his best work as a homilist, for he finds in the uplifting spiritual poetry of the Hebrews messages that he can apply consistently to his view of austere, hopeful, realistic Christianity; his ordinary congregation in Hippo would have…

St. Augustine: Sermons: …collection, Enarrationes in Psalmos (392–418; Enarrations on the Psalms). These are perhaps his best work as a homilist, for he finds in the uplifting spiritual poetry of the Hebrews messages that he can apply consistently to his view of austere, hopeful, realistic Christianity; his ordinary congregation in Hippo would have…

lower vascular plant: Leaves: …simplest are scalelike emergences, or enations, that are not served by vascular tissue (i.e., they have no veins), found in some extinct groups and in modern whisk ferns (Psilotum). The lycophytes have scalelike, needlelike, or awl-shaped “microphylls” with a single, unbranched vein. The sphenophytes have “sphenophylls”—scalelike leaves with a single…

fern: Evolutionary development: …branching stem systems) and the enation theory (that the leaf arose from simple enations, or outgrowths) are the two most popular. The true story seems to be lost in antiquity and perhaps will never be known. Leaves of most modern ferns, with their characteristic fiddleheads, acropetal growth (i.e., “seeking the…

Ethiopian literature: …converted to Christianity and, as Enbaqom (Habakkuk), became prior of the monastery of Debre Libanos, wrote Anqasʾa amin (“Gate of Faith”) to justify his conversion and to persuade apostates to recant. Other similar works were produced, and several were written to defend the miaphysite branch of the Christian faith. Meanwhile…

psoriasis: …for psoriasis, including infliximab (Remicade), etanercept (Enbrel), and guselkumab (Tremfya).

extinguisher moss, any of the plants of the genus Encalypta (subclass Bryidae), which form large tufts on limestone rocks, ledges, and walls. About 8 of the 34 species in the genus are native to North America. They are usually 1 to 3 cm (0.4 to 1.2 inches) tall, with erect capsules (spore cases)

extinguisher moss: …extends below the capsule; in E. ciliata the calyptra is fringed.

Encamp, village, Andorra, on a headstream of the Valira River. Its agricultural economy is supplemented by tourism, especially skiing. Encamp has a broadcasting transmitter of Radio Andorra. Above the village is Engolasters Lake, accessible by cable car. There are facilities for generating

Galapagos Islands, island group of the eastern Pacific Ocean, administratively a province of Ecuador. The Galapagos consist of 13 major islands (ranging in area from 5.4 to 1,771 square miles [14 to 4,588 square km]), 6 smaller islands, and scores of islets and rocks lying athwart the Equator 600

The Encantadas, ten fictional sketches by Herman Melville, published in 1854 in Putnam’s Monthly Magazine as “The Encantadas, or Enchanted Isles,” under the pseudonym Salvator R. Tarnmoor. Seven of the sketches describe the Galapagos Islands in the eastern Pacific Ocean, which Melville had seen

The Encantadas, ten fictional sketches by Herman Melville, published in 1854 in Putnam’s Monthly Magazine as “The Encantadas, or Enchanted Isles,” under the pseudonym Salvator R. Tarnmoor. Seven of the sketches describe the Galapagos Islands in the eastern Pacific Ocean, which Melville had seen

Lin-Manuel Miranda: …(“Two Caterpillars”) for the film Encanto (“Charm”), and the song earned Miranda another Oscar nomination.

computer science: Programming languages: …the addition of support for data encapsulation, which gave rise to object-oriented languages. The original object-oriented language was called Smalltalk, in which all programs were represented as collections of objects communicating with each other via message-passing. An object is a set of data together with the methods (functions) that can…

Encarnación, city, southeastern Paraguay. The city was founded in 1614 on the west bank of the Upper Paraná River, opposite Posadas, Arg., to which it is linked by a bridge completed in 1987. Severely damaged by a tornado in 1926, it is now a busy commercial, manufacturing, and communications

Encarta, multimedia digital encyclopaedia produced by Microsoft Corporation (1993–2009). Initially a CD-ROM product, the Encarta brand later expanded to include an Internet-based incarnation and was bundled with other Microsoft products. The possibility of a digital encyclopaedia was first

Encarta: …1999 the company debuted the Encarta Africana, an encyclopaedia of black history that was the result of a collaboration with scholars, including Henry Louis Gates, Jr., and published a print and digital dictionary, the Encarta World English Dictionary, called the Encarta Webster’s Dictionary of the English Language in subsequent editions.

encaustic painting, painting technique in which pigments are mixed with hot liquid wax. Artists can change the paint’s consistency by adding resin or oil (the latter for use on canvas) to the wax. After the paint has been applied to the support, which is usually made of wood, plaster, or canvas, a

Mesopotamian art and architecture: Neo-Babylonian period: …and surrounded by a double enceinte, or line of fortification, consisting of towered and moated fortress walls. Inside the city the most grandiose effect was obtained by the disposal of public buildings along a wide processional way, leading through the centre of the town to the temple and ziggurat of…

Enceladus, second nearest of the major regular moons of Saturn and the brightest of all its moons. It was discovered in 1789 by the English astronomer William Herschel and named for one of the Giants (Gigantes) of Greek mythology. Enceladus measures about 500 km (310 miles) in diameter and orbits

Encephalartos, genus of 65 species of palmlike cycads in the family Zamiaceae, native to central and southern Africa. Several species are grown as conservatory and houseplants. The genus includes both tuberous and columnar varieties; they sometimes have spiny foliage. As gymnosperms, the plants

encephalitis, from Greek enkephalos (“brain”) and itis (“inflammation”), inflammation of the brain. Inflammation affecting the brain may also involve adjoining structures; encephalomyelitis is inflammation of the brain and spinal cord, and meningoencephalitis is inflammation of the brain and

encephalitis, from Greek enkephalos (“brain”) and itis (“inflammation”), inflammation of the brain. Inflammation affecting the brain may also involve adjoining structures; encephalomyelitis is inflammation of the brain and spinal cord, and meningoencephalitis is inflammation of the brain and

encephalitis lethargica, form of encephalitis that emerged in the early 20th century. An encephalitis lethargica epidemic occurred from 1915 to 1928. The disease was first described medically in 1917, though numerous possible forerunners dating back to the 16th century have been identified.

encephalitis lethargica: An encephalitis lethargica epidemic occurred from 1915 to 1928. The disease was first described medically in 1917, though numerous possible forerunners dating back to the 16th century have been identified.

equine encephalitis, severe viral disease of horses and mules, transmitted by mosquitoes. It sometimes affects birds, reptiles, and humans. There are multiple different types of equine encephalitis, including Eastern equine encephalitis (EEE), Western equine encephalitis (WEE), and Venezuelan

encephalitis: Epidemics of encephalitis: …most common epidemic forms is Japanese encephalitis, which is caused by a mosquito-borne virus and results in acute illness. Japanese encephalitis is found primarily in Asia. Other viral forms of encephalitis, such as St. Louis encephalitis and La Crosse encephalitis, cause sporadic disease in some areas of the United States.…

nervous system: Encephalization: Early in the evolution of vertebrates, a special sensory system became associated with each major part of the brain: the olfactory organs with the forebrain, the eye with the midbrain, and the ear and related organs with the hindbrain. Each of the three sections,…

neural tube defect: …of open neural tube defect, encephalocele, occurs when a meningeal sac containing brain tissue protrudes from the skull. The outlook for affected individuals depends on the amount of nervous tissue involved.

neural tube defect: …of open neural tube defect, encephalocele, occurs when a meningeal sac containing brain tissue protrudes from the skull. The outlook for affected individuals depends on the amount of nervous tissue involved.

encephalitis: …may also involve adjoining structures; encephalomyelitis is inflammation of the brain and spinal cord, and meningoencephalitis is inflammation of the brain and meninges (the membranes covering the brain).

equine encephalitis, severe viral disease of horses and mules, transmitted by mosquitoes. It sometimes affects birds, reptiles, and humans. There are multiple different types of equine encephalitis, including Eastern equine encephalitis (EEE), Western equine encephalitis (WEE), and Venezuelan

brain, the mass of nerve tissue in the anterior end of an organism. The brain integrates sensory information and directs motor responses; in higher vertebrates it is also the centre of learning. The human brain weighs approximately 1.4 kg (3 pounds) and is made up of billions of cells called

inborn error of metabolism: Symptoms and effects on the brain: …disease often appears clinically as encephalopathy (abnormal brain function and structure). Encephalopathy reflects the accumulation of an otherwise normal metabolite that becomes toxic when present in excess concentration. An example is the extreme elevation of the amino acid phenylalanine that accompanies a congenital defect of phenylalanine hydroxylase, the mutant enzyme…

Amy Adams: …later successes as Giselle in Enchanted (2007), an animated and live-action film about a fairy-tale princess in New York City, and as Sister James in Doubt (2008), for which she received another Academy Award nomination. In 2008 she also starred in the comedy Mrs. Pettigrew Lives for a Day and…

Joan Plowright: …as a haughty know-it-all in Enchanted April (1991), Plowright was nominated for a best supporting actress Academy Award. In 2005 she starred as a lonely widow who befriends a young writer in Mrs. Palfrey at the Claremont (2005). Plowright’s later movies included the children’s movies Curious George (2006), for which…

enchanter’s nightshade, any herbaceous perennial plant of the genus Circaea, in the evening primrose family (Onagraceae), that occurs in damp woodlands of the Northern Hemisphere. The plants have slender stems with opposite leaves. The small, white, two-petaled flowers grow in clusters, and the

Guillaume Apollinaire: His first volume, L’Enchanteur pourrissant (1909; “The Rotting Magician”), is a strange dialogue in poetic prose between the magician Merlin and the nymph Viviane. In the following year a collection of vivid stories, some whimsical and some wildly fantastic, appeared under the title L’Hérésiarque et Cie (1910; “The…

Salman Rushdie: Post-fatwa writings: …of the Indian subcontinent, and The Enchantress of Florence (2008), based on a fictionalized account of the Mughal emperor Akbar. The children’s book Luka and the Fire of Life (2010) centers on the efforts of Luka—younger brother to the protagonist of Haroun and the Sea of Stories—to locate the titular…

Stoicism: Later Roman Stoicism: The Encheiridion (Manual) of Epictetus and the Meditations of Marcus Aurelius furthered the sublime and yet personal consolation of the Stoic message and increasingly showed the strength of its rivalry to the burgeoning power of the new Christianity. The mark of a guide, of the religious teacher,…

Arrian: …work by Arrian is the Encheiridion (“Manual”), a manual of the teachings of Epictetus, the Stoic philosopher whose disciple Arrian was. This work was much used in the Middle Ages as a guide to the principles of the monastic life.

Enchi Fumiko was a Japanese novelist best known for her depiction of women’s struggles within Japanese society. Enchi Fumiko was the daughter of Ueda Kazutoshi, a prominent professor of Japanese linguistics at Tokyo University. Even as a small child, she accompanied her father to Kabuki

gastronomy: Latin American: Enchiladas are tortillas dipped in sauce, then rolled up with a filling of pork or chicken and baked or broiled. Tostadas are tortillas fried crisp and sprinkled with onion, chili peppers, grated cheese, or meat. Quesadillas are tortillas folded over a filling of meat, beans,…

Francis Quarles: His first prose work, Enchiridion (1640), was a highly popular book of aphorisms. In the English Civil Wars he is said to have suffered for his allegiance and for writing The Loyall Convert (1644), a pamphlet defending Charles I’s position.

English literature: Late 10th- and 11th-century prose: …several Latin works and the Enchiridion, a textbook on the calendar, notable for its ornate style. Numerous anonymous works, some of very high quality, were produced in this period, including homilies, saints’ lives, dialogues, and translations of such works as the Gospels, several Old Testament books, liturgical texts, monastic rules,…

Johann Eck: His treatise entitled Enchiridion Against the Lutherans (1525) was a summary of contested Catholic beliefs, Protestant objections to them, and answers to these difficulties. The Enchiridion proved to be the most popular of Eck’s works and went through 91 editions in various languages before 1600, making it the…

Erasmus: The wandering scholar: …was Enchiridion militis Christiani (1503/04; Handbook of a Christian Knight). In this work Erasmus urged readers to “inject into the vitals” the teachings of Christ by studying and meditating on the Scriptures, using the spiritual interpretation favoured by the “ancients” to make the text pertinent to moral concerns. The Enchiridion…

Saint Nicodemus the Hagiorite: His Enchiridion of Counsels (1801), a handbook on the religious life, continues to guide modern Greek spirituality. He was proclaimed a saint by the Greek Orthodox church in 1955.

enchondroma, solitary benign cartilaginous tumour that occurs mostly in the shafts of bones of the hands and feet, usually between adolescence and about age 50. Enchondromas are slow-growing tumours. As they grow, they expand and thin the cortex of the parent bone, producing considerable deformity.

enchondroma: …with the lesions produced in enchondromatosis (also called Ollier disease).

Francesco Selmi: ” Selmi’s Enciclopedia di chimica scientifica e industriale, 11 vol. (1868–81), was the first encyclopaedia of chemistry published in Italian.

encyclopaedia: The 20th century and beyond: The Enciclopedia europea was released in Milan between 1976 and 1984. Although consisting largely of brief articles, it had numerous signed long articles of good quality. In Germany the three giants of the German encyclopaedia world—Brockhaus, “Meyer,” “Herder”—continued to produce new editions in the 20th century.

Enciclopedia italiana di scienze, lettere ed arti, (Italian: “Italian Encyclopaedia of Science, Letters, and Arts”), major encyclopaedia of Italy, containing 35 volumes of text and a one-volume index. Work on the encyclopaedia began in 1925 and the volumes were published serially from 1929 to 1936;

encyclopaedia: The 20th century and beyond: Another major Spanish encyclopaedia, the Enciclopedia labor (first issued 1955–60), devoted one volume each to major subject areas, and an index volume provided the key to the total contents. This encyclopaedia was notable for the attention it paid to every Spanish-speaking part of the world.

Enciclopedia universal ilustrada europeoamericana, encyclopaedia published in Madrid, an outstanding reference work of 70 volumes—published between 1905 and 1933—plus a series of supplements. Spanish and Spanish-American biography and gazetteer information are especially strong. Major

Pamplona: …each morning by the famous encierro—“enclosing”—or, more commonly, “running” of the bulls, when they are driven through the streets behind crowds of skillfully dodging men and boys.

Juan del Encina was a playwright, poet, priest, and composer of secular vocal music, who was the first Spanish dramatist to write specifically for performance. After youthful training as a chorister at Salamanca cathedral (c. 1484) and at the University of Salamanca (before 1490), Encina entered

Sunnyvale, city, Santa Clara county, western California, U.S. Adjacent to the cities of Santa Clara and Mountain View, Sunnyvale lies at the southern end of San Francisco Bay, near San Jose. Settled in 1850, it was known as Murphy’s Station (later as Encinal), but it was renamed Sunnyvale in 1912

data encryption, the process of disguising information as “ciphertext,” or data unintelligible to an unauthorized person. Conversely, decryption, or decipherment, is the process of converting ciphertext back into its original format. Manual encryption has been used since Roman times, but the term

Wassily Kandinsky: Munich period: …practically abstract; with the 1911 Encircled, there has definitely developed a kind of painting that, though not just decoration, has no discernible point of departure in the depiction of recognizable objects. After that come such major works as With the Black Arch (1912), Autumn II (1912), and

Vasco Núñez de Balboa: Career in the New World: …on an expedition organized by Martín Fernández de Enciso (1510) to bring aid and reinforcements to a colony founded by Alonso de Ojeda on the coast of Urabá, in modern Colombia. The expedition found the survivors of the colony, led by Francisco Pizarro, but Ojeda had departed. On the advice…

Encke’s Comet, faint comet having the shortest orbital period (about 3.3 years) of any known; it was also only the second comet (after Halley’s) to have its period established. The comet was first observed in 1786 by French astronomer Pierre Méchain. In 1819 German astronomer Johann Franz Encke

Johann Franz Encke: …known for his discovery of Encke’s Division, in the outermost ring of Saturn. From observations of the transits of Venus recorded in 1761 and 1769, he derived a value for the solar parallax (in effect, for the Sun’s distance from the Earth) that, at 8″.57, is close to the presently…

Johann Franz Encke: …known for his discovery of Encke’s Division, in the outermost ring of Saturn. From observations of the transits of Venus recorded in 1761 and 1769, he derived a value for the solar parallax (in effect, for the Sun’s distance from the Earth) that, at 8″.57, is close to the presently…

Johann Franz Encke was a German astronomer who in 1819 established the period of the comet now known by his name (see Encke’s Comet). Encke was educated at Hamburg and the University of Göttingen, where he worked under the direction of Carl Friedrich Gauss. In 1816 Encke became assistant at the

Rabbe Enckell was a Finnish poet, playwright, and critic, a leading representative of the Swedo-Finnish poetic revival that began in the 1920s. Enckell studied art in France and Italy. His first collection of impressionistic nature poems, Dikter, appeared in 1923. In this collection and a sequel,

Rabbe Enckell was a Finnish poet, playwright, and critic, a leading representative of the Swedo-Finnish poetic revival that began in the 1920s. Enckell studied art in France and Italy. His first collection of impressionistic nature poems, Dikter, appeared in 1923. In this collection and a sequel,

Paleo-Siberian languages: Grammatical features: …of verbs, and use of enclitics—an enclitic is a word that is associated with a preceding word), whereas Yukaghir shares certain grammatical categories with some Uralic languages—for instance, the use of distinct conjugations to focus on the roles of major sentence categories (e.g., subject, object, negation): Yukaghir tet mer-ai-mek ‘you…

Sanāʾī: …was translated in English as The Enclosed Garden of Truth (1910).

solid-waste management: Digesting and processing: Enclosed mechanical composting facilities can reduce land requirements by about 85 percent. Mechanical composting systems employ one or more closed tanks or digesters equipped with rotating vanes that mix and aerate the shredded waste. Complete digestion of the waste takes about one week.

enclosed rhyme, in poetry, the rhyming pattern abba found in certain quatrains, such as the first verse of Matthew Arnold’s

enclosed rhyme, in poetry, the rhyming pattern abba found in certain quatrains, such as the first verse of Matthew Arnold’s

enclosure, the division or consolidation of communal fields, meadows, pastures, and other arable lands in western Europe into the carefully delineated and individually owned and managed farm plots of modern times. Before enclosure, much farmland existed in the form of numerous, dispersed strips

ENCODE, collaborative data-collection project begun in 2003 that aimed to inventory all the functional elements of the human genome. ENCODE was conceived by researchers at the U.S. National Human Genome Research Institute (NHGRI) as a follow-on to the Human Genome Project (HGP; 1990–2003), which

combinatorics: Orthogonal arrays and the packing problem: …in the construction of error-correcting codes. A row vector c′ is taken as a code word if and only if c′H = 0. The code words then are of length n and differ in at least t + 1 places. If t = 2u, then u or fewer errors of…

primitive culture: The closed regional market system: …been appropriately labeled the “encogido syndrome,” meaning a nearly utter lack of self-confidence.

history of Latin America: Indians and Spaniards: …there were indigenous units; the encomendero (holder of the grant) could at least initially receive only what the ruler had received before him. The larger islands were inhabited by the Arawak, a sedentary if modestly developed people with kingdoms, rulers, nobles, and obligatory labour mechanisms. Their ruler was called a…

Mesopotamian religion: Sumerian literature: …over and over again the encomiast, the official praiser, whose task it was to sing these hymns, closed with the standing phrase: “O [the name of a deity or human hero], thy praise is sweet.” The same phrase is common also at the end of myths and epics, two further…

encomienda, in Spain’s American and Philippine colonies, legal system by which the Spanish crown attempted to define the status of the indigenous population. It was based upon the practice of exacting tribute from Muslims and Jews during the Reconquista (“Reconquest”) of Muslim Spain. Although the

encomium, a prose or poetic work in which a person, thing, or abstract idea is glorified. Originally an encomium was a Greek choral song honouring the hero of the Olympic Games and sung at the victory celebration at the end of the Games. The Greek writers Simonides of Ceos and Pindar wrote some of

mental disorder: Other childhood disorders: …during the day or night), encopresis (the repeated voiding of feces into inappropriate places), sleepwalking, and night terror. These symptoms are not necessarily evidence of emotional disturbance or of some other mental illness. Behavioral methods of treatment are usually effective.