yellow poplar: see magnolia.

yellow journalism: see newspaper.

yellow jacket: see wasp.

yellow fever, acute infectious disease endemic in tropical Africa and many areas of South America. Epidemics have extended into subtropical and temperate regions during warm seasons. In 1878 a severe outbreak in the Mississippi Valley killed about 20,000; the last epidemic in the United States occurred in New Orleans in 1905. Yellow fever is caused by a virus transmitted by the bite of the female Aedes aegypti mosquito, which breeds in stagnant water near human habitations. A form of the disease called sylvan yellow fever is transmitted in tropical jungles by other species of mosquitoes that live in trees.

At the end of the 19th cent., yellow fever was highly prevalent in the Caribbean, and a way of controlling it had to be found before construction of the Panama Canal could be undertaken. In 1900 an American commission headed by Walter Reed and including James Carroll, Jesse Lazear, and Aristides Agramonte gathered in the U.S. Army's Camp Columbia in Cuba. Through their experiments they proved the theory of C. J. Finlay that yellow fever was a mosquito-borne infection. Within the next few years, W. C. Gorgas, an army physician and sanitation expert, succeeded in controlling the disease in the Panama Canal Zone and other areas in that part of the world by mosquito-eradication measures. The later development of an immunizing vaccine and strict quarantine measures against ships, planes, and passengers coming from known or suspected yellow-fever areas further aided control of the disease.

Yellow fever begins suddenly after an incubation period of three to five days. In mild cases only fever and headache may be present. The severe form of the disease commences with fever, chills, bleeding into the skin, rapid heartbeat, headache, back pains, and extreme prostration. Nausea, vomiting, and constipation are common. Jaundice usually appears on the second or third day. After the third day the symptoms recede, only to return with increased severity in the final stage, during which there is a marked tendency to hemorrhage internally; the characteristic "coffee ground" vomitus contains blood. The patient then lapses into delirium and coma, often followed by death. During epidemics the fatality rate was often as high as 85%. Although the disease still occurs, it is usually confined to sporadic outbreaks.

yellow daisy: see black-eyed Susan.

Yellow Sea or Huanghai [yellow sea], arm of the Pacific Ocean, between China and Korea. It has a maximum depth of 500 ft (152 m). Bohai, Korea Bay (or West Korea Bay), and the Liaodong Gulf are its major inlets. The Huang He, Huai, Liao, and Yalu rivers empty into it. South of the Korean peninsula, it becomes the East China Sea. The name sometimes appears as Hwang-hai.

Yellow River, China: see Huang He.

Yellow Emperor, Mandarin Huangdi, legendary Chinese ruler and culture hero; tradition holds that he reigned from 2697 B.C. to 2597 B.C. He is one of the mythical prehistoric emperors who supposedly created the basic elements of Chinese civilization. His wife is said to have developed silk production. Along with the semimythical Lao Tzu, he was associated in the traditional Chinese folk culture with the founding of Taoism.

Yellow Book, English illustrated quarterly published (1894-97) in book form in London. Henry Harland was literary editor, and Aubrey Beardsley, whose exotic and provocative drawings brought immediate attention to the publication, was art editor until 1896. The Yellow Book was a miscellany of short stories, articles, poetry, and drawings. It was able to draw material from writers with wide differences of style and viewpoint, but its emphasis was on the bizarre, the "modern," and the aesthetic. It included among its contributors Oscar Wilde, Max Beerbohm, John Davidson, Richard Le Gallienne, William Butler Yeats, Ernest Dowson, and Arnold Bennett.

or tulip poplar or yellow poplar

Lofty North American ornamental and timber tree (Liriodendron tulipifera) of the magnolia family, not related to true poplars. It occurs in mixed hardwood stands in eastern North America. It is taller than all other eastern broad-leaved trees (up to 197 ft, or 60 m), and its trunk often has a diameter greater than 7 ft (2 m). Long-stemmed, bright-green leaves have two to four side lobes and blunted tips. Yellowish-green tuliplike flowers have six petals, orange at their bases, and three bright-green sepals. Other characteristics include conelike clusters of winged fruits; aromatic, purplish-brown twigs; stunning golden-yellow autumn leaves; winter buds resembling a duck's bill; and resistance to pests and diseases. The wood is used to manufacture furniture parts, plywood panels, paper, boxes, and crates.

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In newspaper publishing, the use of lurid features and sensationalized news in newspaper publishing to attract readers and increase circulation. The phrase was coined in the 1890s to describe tactics employed in the furious competition between two New York papers, Joseph Pulitzer's World and William Randolph Hearst's Journal. When Hearst hired away from Pulitzer a cartoonist who had drawn the immensely popular comic strip “The Yellow Kid,” another cartoonist was hired to draw the comic for the World; the rivalry excited so much attention that the competition was dubbed yellow journalism. Techniques of the period that became permanent features of U.S. journalism include banner headlines, coloured comics, and copious illustrations.

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Acute infectious tropical disease, sometimes occurring in temperate zones. Abrupt onset of headache, backache, fever, nausea, and vomiting is followed by either recovery with immunity or by higher fever, slow pulse, and vomiting of blood. Patients may die in a week. Jaundice is common (hence the name). One of the world's great plagues for 300 years, it is caused by a virus transmitted by several species of mosquitoes. Carlos Finlay suggested and Walter Reed proved this means of spread, leading to near elimination of the disease through mosquito control (see William Gorgas). Treatment consists of supportive care, particularly fever reduction. Control of mosquitoes near cities and live-virus vaccines—developed by Max Theiler (1899–1972), who won a 1951 Nobel Prize for his work—have made yellow fever completely preventable.

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or yellow bunting

Songbird species (Emberiza citrinella, family Emberizidae) found from Britain to central Asia. The name is derived from the German Ammer (“bunting”). Yellowhammers are 6 in. (16 cm) long and have a streaked brown body, yellow-tinged head and breast, and a rapid song. In the southern U.S., the yellow-shafted flicker is called yellowhammer because of its drumming.

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Chinese Huang Hai

Large inlet of the western North Pacific Ocean, between northeastern China and the Korean peninsula. Renowned for its fishing grounds, it connects with the East China Sea on the south; the Shandong Peninsula extends into it from the west. Two major arms of it are the Bo Hai (northwest) and Korea Bay (north). Excluding the Bo Hai, it has an area of about 161,000 sq mi (417,000 sq km) and a maximum depth of 338 ft (103 m). It derives its name from the colour of the silt-laden water discharged into it by major Chinese rivers, including the Liao and the Huang He (Yellow River), both of which flow into the Bo Hai. Leading port cities include Qingdao and Dalian in China, Inch'ŏn in South Korea, and Namp'o in North Korea.

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or Huang Ho English Yellow River

River, northern, central, and eastern China. The second longest river in China and one of the world's longest, it flows 3,395 mi (5,464 km) from the Plateau of Tibet generally east to the Yellow Sea (Huang Hai). In its lower reaches it has often overflowed its banks, flooding vast areas of rich farmland. Its outlet has shifted over the years to enter the Yellow Sea at points as far apart as 500 mi (800 km). Irrigation and flood-control works have been maintained for centuries, and dams, begun in the mid-1950s, exploit the river's hydroelectric potential.

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or Huang-ti(Chinese; Yellow Emperor)

Third of ancient China's mythological emperors and a patron saint of Daoism. According to legend, he was born in 2704 BC and became emperor in 2697. He is remembered as a paragon of wisdom who established a golden age, seeking to create an ideal kingdom in which his people would live in keeping with natural law. Tradition holds that his reign saw the introduction of wooden houses, carts, boats, the bow and arrow, writing, and governmental institutions. His wife was reputed to have taught women how to breed silkworms and weave silk.

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