dendrochronology, the scientific discipline concerned with dating and interpreting past events, particularly paleoclimates and climatic trends, based on the analysis of tree rings. Samples are obtained by means of an increment borer, a simple metal tube of small diameter that can be driven into a

brachiation, in animal behaviour, specialized form of arboreal locomotion in which movement is accomplished by swinging from one hold to another by the arms. The process is highly developed in the gibbon and siamang, which are anatomically adapted for it in the length of their forelimbs, their long

dance: Tribal dance: Joan Lawson described the tree-worship dance performed both in Australia and up the Amazon River:

Henry Treece was an English poet and historical novelist whose ability to bring the ancient world to life in fiction makes his work especially appealing to young readers. As a poet, he—together with J.F. Hendry—was a founder of the New Apocalypse movement, a reaction against the politically

treecreeper, any of more than a dozen species of small slender birds, with downcurved bills, that spiral up tree trunks in search of insects. They are variously classified in the families Certhiidae and Climacteridae. The nine species of the genus Certhia constitute most of the family Certhiidae

tree frog, any of more than 800 species of typically arboreal frog occurring on all continents except Antarctica and belonging to one of several families of the order Anura. Of these, the hylid, or “true,” tree frogs from the family Hylidae are the most numerous. Hylids are usually slender, less

treehopper, (family Membracidae), any of approximately 3,200 species of insects (order Homoptera) that are easily recognized by their vertical face and grotesquely enlarged thorax, which may extend anteriorly over the head to form one or more spines and expands posteriorly over the body to form a

Guy Ben-Ner: …Biennale with his video installation Treehouse Kit, which consisted of a prefabricated tree sculpture and an instructional video featuring the artist. In 2007 he completed Stealing Beauty, a mischievous guerrilla video of sorts that he filmed without permission in several IKEA department stores. Using IKEA’s showrooms as if they were…

Scott Joplin: …most of Joplin’s efforts involved Treemonisha, which synthesized his musical ideas into a conventional, three-act opera. He also wrote the libretto, about a mythical Black leader, and choreographed it. Treemonisha had only one semipublic performance during Joplin’s lifetime; he became obsessed with its success, experienced a mental health crisis in…

treen, small wooden objects in daily domestic or farm use and in use in trades and professions. Treen includes a wide variety of objects mostly associated with tableware, the kitchen, games, personal adornment, and toilet articles. The word is never applied to objects larger than a spinning wheel

hand tool: Drilling and boring tools: …holes for wooden pins (treenails, or trunnels) or bolts for connections. The modern auger bit has a screw ahead of the cutting edges that pulls the auger into the workpiece. This screw provides an automatic feed and relieves the worker of the necessity of pushing the tool. Although the…

Saale Glacial Stage: These are the Drente, Treene, and Warthe substages. The Drente and Warthe represent periods of glacial advance, or maxima, whereas the Treene represents an interstadial period of glacial retreat between the early Drente and the late Warthe. In the region of central Europe, the Saale is represented by three…

sittella, any of about two species of Australasian birds of the genus Daphoenositta, sometimes placed in the nuthatch family, Sittidae, but many classifications group them in their own family, Neosittidae. They resemble nuthatches in build—short-tailed and large-footed—and in behaviour, but they

Joyce Kilmer: His most famous poem, “Trees,” appeared in Poetry magazine in 1913. Its immediate and continued popularity has been attributed to its combination of sentiment and simple philosophy. His books include Trees and Other Poems (1914); The Circus and Other Essays (1916); Main Street and Other Poems (1917); and Literature…

Steve Buscemi: Directing and other activities: …in his first feature film, Trees Lounge, about an unemployed car mechanic who spends his days at a local bar. Inspired by his own life at age 19, the dramedy received largely positive reviews and was especially noted for its depiction of blue-collar workers. He later helmed Animal Factory (2000),…

The Trees, novel by Conrad Richter, published in 1940. It was the first novel in a trilogy published collectively as The Awakening Land. The other novels in the trilogy are The Fields and The

Percival Everett: The Trees, Dr. No, and James: Following Telephone, his mystery thriller The Trees (2021) was short-listed for the Booker Prize and won the Anisfield-Wolf Book Award. His novel Dr. No (2022), about a math professor whose alter ego is an expert on nothing, won the PEN/Jean Stein Book Award and was a finalist for the National…

terefah, any food, food product, or utensil that, according to the Jewish dietary laws (kashruth, q.v.), is not ritually clean or prepared according to law and is thus prohibited as unfit for Jewish use. Terefah is thus the antithesis of kosher (“fit”). The broad connotation of terefah derives from

terefah, any food, food product, or utensil that, according to the Jewish dietary laws (kashruth, q.v.), is not ritually clean or prepared according to law and is thus prohibited as unfit for Jewish use. Terefah is thus the antithesis of kosher (“fit”). The broad connotation of terefah derives from

Montgomery, town, Powys county, historic county of Montgomeryshire, eastern Wales. It is situated just west of the border with Shropshire, England, 8 miles (13 km) south of Welshpool. In the 11th century the Norman Roger de Montgomery, 1st earl of Shrewsbury, built his castle at Hendomen, northwest

target theory, in biology, the concept that the biological effects of radiations such as X rays result from ionization (i.e., the formation of electrically charged particles) by individual quanta, or photons, of radiation that are absorbed at sensitive points (targets) in a cell. It is supposed

Holywell, town, historic and present county of Flintshire, northeastern Wales. It is situated near the River Dee estuary. The holy well for which the town is named is on the spot where in the 7th century the head of the Celtic St. Winifred (Gwenffrwd) is said to have fallen when she was

knot: The overhand knot is the simplest type of knot and is used to make a knob in a rope, string, or cord. It is used for tying packages, to keep rope ends from fraying, and as a first step in making more complex knots such as…

terefah, any food, food product, or utensil that, according to the Jewish dietary laws (kashruth, q.v.), is not ritually clean or prepared according to law and is thus prohibited as unfit for Jewish use. Terefah is thus the antithesis of kosher (“fit”). The broad connotation of terefah derives from

Monmouth, town, historic and present county of Monmouthshire (Sir Fynwy), southeastern Wales. It is situated at the confluence of the Rivers Wye and Monnow on the English border. The town of Monmouth, granted its first royal charter in 1256, became important as the market for a rich agricultural

Cornish literature: The Tregear Homilies) is the longest text in historical Cornish, the form of the language extant prior to the language’s disappearance by the early 19th century and its revival in the 20th. This manuscript renders into Cornish 12 sermons by Bishop Edmund Bonner of London;…

Mario Benedetti: His novel La tregua (1960; The Truce) was widely read, as was his allegorical novel El cumpleaños de Juan Angel (1971; Juan Angel’s Birthday). Benedetti had the misfortune of peaking as a writer at the same time as Carlos Fuentes, Gabriel García Márquez, Mario Vargas Llosa, and others who brought…

disaccharide: Another important disaccharide, trehalose, which is found in single-celled organisms and in many insects, also consists of two molecules of glucose and an α-linkage, but the linkage is distinct from the one found in maltose.

dog sports: Herding and treibball: Treibball (a German word commonly translated as “push ball”) is a timed herding competition that requires no other animals and is amenable to dogs of all sizes and breeds, though herding dogs tend to have an advantage. The object of the competition is for a…

Côte d’Ivoire: Urban environment: Treichville, located behind the fishing village of Anoumabo, owes its importance to the boom in colonial trade that followed World War I. It remained a very small town until 1934, when the seat of colonial government was moved to Abidjan from Bingerville. Urban growth was…

lake: Cause and characteristics: The observed uninodal periods of Loch Treig and Loch Earn, Scotland; Lago di Garda, Italy; Lake Vetter, Sweden; and Lake Erie, North America, are approximately nine, 14.5, 43, 179, and 880 minutes, respectively.

Treinta y Tres, city, east-central Uruguay, near the Olimar Grande River. It is the commercial and manufacturing centre for an agricultural and pastoral hinterland. Cattle and sheep are raised widely; wheat, corn (maize), oats, and linseed are the chief crops. Treinta y Tres lies on the

Heinrich von Treitschke: …evident in his magnum opus, Deutsche Geschichte im 19. Jahrhundert, 5 vol. (1879–94; Treitschke’s History of Germany in the Nineteenth Century), which covers the period from 1800 to 1848. Treitschke did not live to finish writing this work. His most important other works are the essays collected in Historische und…

Heinrich von Treitschke was a German historian and political writer whose advocacy of power politics was influential at home and contributed to distrust of Germany abroad. The son of a Saxon general, Treitschke studied at Bonn and Leipzig. He taught history and politics at the University of Leipzig

Danny Trejo is an American actor, activist, and author known for his rough looks, his philanthropy, and his large body of work as a character actor. Trejo has played more than 400 roles in film and television, most notably as the titular character in the Machete films (2010 and 2013) and in various

Danny Trejo is an American actor, activist, and author known for his rough looks, his philanthropy, and his large body of work as a character actor. Trejo has played more than 400 roles in film and television, most notably as the titular character in the Machete films (2010 and 2013) and in various

Orange Free State: …farmers of Dutch descent, called trekboers or Boers, began to settle the area. After 1836 came the Great Trek, a migratory movement in which larger numbers of Boer farmers seeking freedom from British rule moved north across the Orange River. In 1848 the British annexed the territory between the Orange…

Trekvaart, system of canals in the Low Countries, built in the 17th century and used exclusively by boats carrying passengers and parcels. The system of canals connected the main towns and cities of the area, its construction and operation being organized by local authorities. Newly built sections

Sir Arthur Wing Pinero: In a less serious vein, Trelawny of the “Wells” (written for the Royal Court Theatre and produced in 1898) portrayed theatrical company life in the old style of the 1860s—already then a vanishing tradition—and The Gay Lord Quex (1899) was about a theatrical rake of no placeable period but having…

Edward Trelawny was a British governor of Jamaica from April 1738 to September 1752 who ended a long-standing war between white planters and descendants of formerly enslaved Black workers known as Maroons. Trelawny was a member of a noted Cornish family and the son of Sir Jonathan Trelawny, bishop

Edward John Trelawny was an English author and adventurer, the friend of Percy Bysshe Shelley and Lord Byron, whom he portrayed brilliantly in his books. Trelawny was a handsome, dashing, and quixotic personality from an old and famous Cornish family. He was brought up in London and went to a

Trelleborg, town and port, Skåne län (county), southern Sweden, on the Baltic Sea. During the Middle Ages it was an important herring-fishing and commercial centre, but it declined after the herring left the area in the 15th century. After being plundered during war (1563–70) between Denmark and

Regina M. Anderson was an American librarian, playwright, and patron of the arts whose New York City home was a salon for Harlem Renaissance writers and artists. Anderson attended several colleges, including Wilberforce University in Ohio and the University of Chicago. She received a Master of

Regina M. Anderson was an American librarian, playwright, and patron of the arts whose New York City home was a salon for Harlem Renaissance writers and artists. Anderson attended several colleges, including Wilberforce University in Ohio and the University of Chicago. She received a Master of

trellis, framework on which trees and climbing plants are trained. It is usually constructed of long, narrow wood or metal slats that are crisscrossed to produce square or diamond-shaped spaces. Trellises may also be made of any open construction, such as untrimmed branches loosely nailed or woven

telecommunication: Convolutional encoding: …described above are employed in trellis coding, a coding scheme used in high-speed modems. However, instead of the sequence of bits that is produced by a convolutional encoder, a trellis encoder produces a sequence of modulation symbols. At the transmitter, the channel-encoding process is coupled with the modulation process, producing…

river: Drainage patterns: Trellis (or espalier) drainage patterns result from adjustment to tight regional folding in which the folds plunge. Denudation produces a zigzag pattern of outcrops, and adjustment to this pattern produces a stream net in which the trunks are aligned on weak rocks exposed along fold…

Herculaneum: …middle class (such as the Trellis House), also finely decorated, or with commercial houses and workshops.

modem: The second generation: …of coded modulation known as trellis-coded modulation, or TCM. Seven years later an upgraded V.32 standard was issued, permitting 14.4-kilobit-per-second full-duplex data transmission over a single PSTN circuit.

Cannabaceae: Major genera and species: The genus Trema, closely related to Celtis, comprises about 40 species of small evergreen trees. Small genera include Aphananthe, Chaetachme, Gironniera, Lozanella, and Pterocletis; the taxonomy of Parasponia is contentious and it is frequently placed within Trema. Older authorities included the two genera Cannabis and Humulus in…

Tremadocian Stage, lowermost of the two standard worldwide divisions of the Lower Ordovician Series and lowest of the seven stages within the Ordovician System. It encompasses all rocks formed during the Tremadocian Age, which spanned the interval between 485.4 million and 477.7 million years ago.

Tremadocian Stage, lowermost of the two standard worldwide divisions of the Lower Ordovician Series and lowest of the seven stages within the Ordovician System. It encompasses all rocks formed during the Tremadocian Age, which spanned the interval between 485.4 million and 477.7 million years ago.

Rose Tremain is a British novelist whose books often dramatize a moment of truth in the lives of lonely outsiders. After receiving a degree in English from the University of East Anglia in 1967, Tremain worked for the British Printing Corporation and wrote several nonfiction works about woman

bear: Evolution and classification: Genus Tremarctos (spectacled bear) 1 species of the Andes Mountains of South America.

spectacled bear, (Tremarctos ornatus), the only South American bear of the family Ursidae. It inhabits the northern and central Andes Mountains, dwelling primarily in forested areas, and it feeds mainly on shoots and fruit. The spectacled bear is the only bear species found south of the Equator.

Jonas Lie: …eller liv nordpå (1872; The Barque “Future,” 1879), followed. Two novels from his Naturalistic period are Livsslaven (1883; “The Life Convict,” Eng. trans.One of Life’s Slaves, 1895), which tells of the social misfortunes of a boy born out of wedlock, and Familien paa Gilje (1883; The Family at Gilje, 1920),…

fluke, any member of the invertebrate class Trematoda (phylum Platyhelminthes), a group of parasitic flatworms that probably evolved from free-living forms millions of years ago. There are more than 10,000 species of flukes. They occur worldwide and range in size from about 5 millimetres (0.2 inch)

fluke, any member of the invertebrate class Trematoda (phylum Platyhelminthes), a group of parasitic flatworms that probably evolved from free-living forms millions of years ago. There are more than 10,000 species of flukes. They occur worldwide and range in size from about 5 millimetres (0.2 inch)

snakeroot poisoning: …and grazing animals caused by trematol, a poisonous alcohol present in white snakeroot (Ageratina altissima), a plant found in North America. When grazing is scarce, cattle may feed on snakeroot and develop a syndrome called trembles. Human poisoning, often called milk sickness, most commonly results from the

amphibian: Annotated classification: †Family Trematopidae (trematopids) Upper Pennsylvanian to Lower Permian. Vertebrae weakly ossified, large intercentrum. †Family Dissorophidae (dissorophids) Subclass Lissamphibia (lissamphibians) Lower Triassic to

Polish literature: Didactic element in prose and poetry: Two other outstanding poets were Stanisław Trembecki, whose works are models of stylistic fluency, and Kajetan Węgierski, a freethinker and admirer of Voltaire who is notorious for his lampoons of influential personalities and fashions.

scrapie, fatal neurodegenerative disease of sheep and goats. Scrapie has been endemic in British sheep, particularly the Suffolk breed, since the early 18th century. Since that time the disease has been detected in countries worldwide, with the exception of Australia and New Zealand, as well as in

Father Joseph was a French mystic and religious reformer whose collaboration with Cardinal de Richelieu (the “Red Eminence”) gave him powers akin to those of a foreign minister, especially during Richelieu’s ambitious campaign to finance France’s participation in what became known as the Thirty

Canadian literature: The Quiet Revolution: In 1968 the young playwright Michel Tremblay revolutionized Quebec theatre with Les Belles-Soeurs (“The Sisters-in-Law”; Eng. trans. Les Belles-Soeurs), which was first read at the Centre d’Essai des Auteurs Dramatiques (Centre for Dramatic Authors), established in 1965 to give a forum to Quebec playwrights. The “new Quebec theatre” ushered in…

snakeroot poisoning: …and develop a syndrome called trembles. Human poisoning, often called milk sickness, most commonly results from the consumption of the milk of poisoned animals. Symptoms in humans include loss of appetite, nausea, weakness, abdominal discomfort, reddened tongue and mucous membranes, and abnormal acidity of the blood, with accumulation of

Abraham Trembley was a Swiss naturalist, best known for his studies of the freshwater hydra, mainly Chlorohydra viridissima. His extensive systematic experiments foreshadowed modern research on tissue regeneration and grafting. Trembley’s experiments demonstrated the hydra’s ability, when cut in

aspen: tremula) and the American quaking, or trembling, aspen (P. tremuloides) are similar, reaching a height of 27 metres (90 feet). P. tremuloides is distinguished by its leaves, which have more pointed tips, and it grows by root suckers. Individual clones of the plants persist for thousands of years even…

Steve Earle: television dramas The Wire and Treme (both produced by David Simon) and in the comedy-thriller film Leaves of Grass (2009). Earle’s debut novel, I’ll Never Get out of This World Alive (2011), was published shortly after the release of the album of the same name.

Basidiomycota: …including those of the genus Tremella (40 species), so called because they have jellylike fruiting bodies. Frequently brightly coloured (especially yellow and orange) or white, the fungi occur on decaying wood after heavy rains in late summer.

fungus: Annotated classification: Order Tremellales Parasitic on mosses, vascular plants, or insects, although most are saprotrophic; basidiocarps well-formed, appearing as inconspicuous horny crusts when dry but usually bright-coloured to black gelatinous masses after a rain; example genera include Tremella, Trichosporon, and Christiansenia. Class Dacrymycetes

fungus: Annotated classification: Class Tremellomycetes Parasitic or saprotrophic; if present, parenthesome separated into cup-shaped sections; gelatinous fruiting bodies may be absent; includes 3 orders. Order Cystofilobasidiales Parasitic and pathogenic on plants (causing black canker of parsnips), may be saprotrophic; dolipores present; may lack parenthesomes;

Camilo José Cela: …the narrative style known as tremendismo, a tendency to emphasize violence and grotesque imagery.

horntail: …North American species is the pigeon tremex (Tremex columba). The adult is about 3.75 cm (1.5 inches) long and has a black and brown body with yellow stripes and yellow legs. The most common British species is Urocerus gigas, which feeds on the wood of pine trees.

psoriasis: (Remicade), etanercept (Enbrel), and guselkumab (Tremfya).

cephalopod: Reproduction and life cycles: In the argonaut and the blanket octopus (Tremoctopus) the males differ in appearance and size from the females.

William Christian: …whereupon the Countess of Derby, Charlotte de la Tremoille, initiated a fruitless attempt to ransom her husband’s life through the surrender of the island to Parliament. Christian headed a revolt against the countess, but at the same time he negotiated independently with the Parliamentarians. In October of 1651, Christian cooperated…

La Trémoille Family: Louis III’s son Claude (1566–1604) at first fought in the campaigns against the Huguenots under Henry III but then changed sides, joining the Protestant king of Navarre, Henry III, in 1586. After Henry de Navarre became King Henry IV, of France, Claude was made a peer (1595).

La Trémoille Family: …Marignan in 1515, his grandson François (1502–41) succeeded to the family estates. Through his marriage to Anne de Laval, granddaughter of Frederick of Aragon, deposed king of Naples, the family derived its pretension to the kingdom of Naples and the claim to recognition at the French court as foreign princes.…

Georges de La Trémoille was a powerful lord who exercised considerable influence over Charles VII of France. At first allied with the duke of Burgundy in the power struggle that continued for many years during Charles VI’s madness, La Trémoille switched his loyalty when the rival faction, the

La Trémoille Family: A Pierre de La Trémoille is recorded as early as the 11th century, but the family’s ascendance dates from the 15th century. Early family members fought in several crusades. Gui (d. 1397) went with John the Fearless, duke of Burgundy, on the crusade to Hungary, was taken prisoner…

Marie-Anne de la Trémoille, princess des Ursins was a French noblewoman who exercised great influence in the government of Spain between 1701 and 1714, during the period of the War of the Spanish Succession. Ursins moved to Italy with her first husband, and after his death she married an Italian

amphibole: Chemical composition: Complete substitution extends from tremolite [Ca2Mg5Si8O22(OH)2] to ferro-actinolite [Ca2Fe5Si8O22(OH)2]. Actinolite is the intermediate member of the tremolite-ferro-actinolite series. The compositional range from about 0.9 Mg7Si8O22(OH)2 to about Fe2

amphibole: Chemical composition: …exist between anthophyllite and the tremolite-actinolite series. Compositional gaps also exist between the cummingtonite-grunerite series and other calcic amphiboles. Consequently, coexisting pairs of anthophyllite-tremolite and grunerite-ferroactinolite are found together in some rocks. Sodium-bearing amphiboles are represented by the glaucophane [Na2Mg3Al2Si8O22(OH)2]–riebeckite [Na2Fe2+3

amphibole: Chemical composition: …the intermediate member of the tremolite-ferro-actinolite series. The compositional range from about 0.9 Mg7Si8O22(OH)2 to about Fe2Mg5Si8O22(OH)2 is represented by the orthorhombic amphibole known as anthophyllite. The monoclinic cummingtonite-grunerite series exists from about Fe2Mg2Si

sound: Other effects on tone: …slow change in pitch) and tremolo (a periodic slow change in amplitude) also aid the analysis of steady-state sounds.

earthquake, any sudden shaking of the ground caused by the passage of seismic waves through Earth’s rocks. Seismic waves are produced when some form of energy stored in Earth’s crust is suddenly released, usually when masses of rock straining against one another suddenly fracture and “slip.”

Kevin Bacon: Breakthrough in Footloose and later film career: …Big Picture (1989), Flatliners (1990), Tremors (1990), and He Said, She Said (1991). During this period he also took on smaller character roles, including memorable performances in Planes, Trains & Automobiles (1987), Oliver Stone’s JFK (1991) with Kevin Costner and Tommy Lee Jones, and A Few Good Men (1992), supporting…

Yelizaveta Alekseyevna Tarakanova was an adventuress and pretender to the Russian throne who claimed to be the daughter of the unmarried empress Elizabeth (reigned 1741–62) and Count Aleksey G. Razumovsky. She claimed to have been reared in St. Petersburg, but she was probably not Russian, and her

Tren de Aragua, Venezuela’s most powerful and far-reaching criminal organization. The organization emerged in the early 2010s as a prison gang in the Tocorón penitentiary in the Venezuelan state of Aragua but grew into a transnational organization with operations across South America. Its expansion

Saint Austell, town (parish), Cornwall unitary authority, southwestern England. It lies just inland of St. Austell Bay on the English Channel. St. Austell was originally called Trenance and takes its present name from a hermit named St. Austol. England’s most important kaolin (china clay) deposits

Carlo Fassi: …champion Fassi coached was American Jill Trenary, who won her gold medal in 1990. Fassi was with two of his skaters, American Nicole Bobek and Romanian Cornel Gheorge, at the 1997 World Championships in Lausanne, Switzerland, when he had a fatal heart attack. He coauthored (with Gregory Smith) Figure Skating…

deep-sea trench, any long, narrow, steep-sided depression in the ocean bottom in which occur the maximum oceanic depths, approximately 7,300 to more than 11,000 metres (24,000 to 36,000 feet). They typically form in locations where one tectonic plate subducts under another. The deepest known

coal mining: Area strip mining: …is flat, commences with a trench or “box cut” made through the overburden to expose a portion of the coal seam. This trench is extended to the limits of the property in the strike direction. After coal removal, a second cut is made parallel to the first one, and the…

Jean Paul Gaultier: …jackets, textured or patterned stockings, trench coats of all sorts, baggy pants, flowing skirts, and the horizontally striped sailor’s shirts that became the signature of his style. Gaultier received most of his thematic inspiration from astrology, religious symbols, Celtic designs, calligraphy, tattoos, and regional apparel from around the world.

trench fever, infectious disease characterized by sudden onset of fever, headache, pain behind the eyes, weakness, sore muscles and joints, and often severe pain in the back and shins. There may be one period of fever, or the fever may recur several times at intervals of four to five days. The

Homer Fordyce Swift: …one of many contributors to Trench Fever, a report written in 1918 for the American Red Cross Commission. Between 1914 and 1948 he also contributed articles to books on internal medicine and infectious diseases.

immersion foot, a painful disorder of the foot involving damage to the skin, nerves, and muscle that is caused by prolonged exposure to cold dampness or by prolonged immersion in cold water. See

solid-waste management: Constructing the landfill: …be made below grade, the trench method of construction may be followed. Where this is not feasible because of topography or groundwater conditions, the area method may be practiced, resulting in a mound or hill rising above the original ground. Since no ground is excavated in the area method, soil…

Vincent gingivitis, acute and painful infection of the tooth margins and gums that is caused by the symbiotic microorganisms Bacillus fusiformis and Borrelia vincentii. The chief symptoms are painful, swollen, bleeding gums; small, painful ulcers covering the gums and tooth margins; and

back-arc basin: …be forced oceanward, causing the trench to “roll back” over the subducting plate, or it may serve as a “sea anchor” by remaining fixed in place relative to the top of the subducting plate. In the latter case, the enlargement of the basin forces the trailing part of the overlying…