Encyclopædia Britannica Australia -

Encyclopedias since 1768

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Bacillariophyceae ... backlight

Bacillariophyceae: (from the article "Bacillariophyceae") class of fuccous algae, commonly known as diatoms, in the division Chromophyta. See diatom.
bacillite: (from the article "bacillite") in geology, a type of crystallite (q.v.).crystallite shapecrystallite...The faster-growing faces of a cry
bacillus: (genus Bacillus), any of a group of rod-shaped, gram-positive, aerobic or (under some conditions) anaerobic bacteria widely found in soil and water. The term bacillus in a general sense has been applied to all cylindrical or rodlike bacteria. The largest ...
bacillus: (from the article "bacteria") Individual bacteria can assume one of three basic shapes: spherical (coccus), rodlike (bacillus), or curved (vibrio, spirillum, or spirochete). Considerable variation is seen in the actual shapes of bacteria, and cells can be stretched or compressed in one dimension. Bacteria ...
Bacillus alvie: (from the article "beekeeping") European foulbrood is caused by a nonsporeforming bacterium, Streptococcus pluton, but Bacillus alvie and Acromobacter eurydice are often associated with Streptococcus pluton. This disease is similar in appearance to American foulbrood. In some instances it severely affects the colonies, but ...
Bacillus anthracis: (from the article "anthrax") acute, infectious, febrile disease of animals and humans caused by Bacillus anthracis, a bacterium that under certain conditions forms highly resistant spores capable of persisting and retaining their virulence for many years. Although anthrax most commonly affects grazing animals such ...
Bacillus cereus: (from the article "bacillus") Bacillus cereus sometimes causes spoilage in canned foods and food poisoning of short duration. B. subtilis, also widely disseminated, is a common contaminant of laboratory cultures (it plagued Louis Pasteur in many of his experiments) and is often found on ...
Bacillus fusiformis: (from the article "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 ...
Bacillus larvae: (from the article "beekeeping") American foulbrood, caused by a spore-forming bacterium, Bacillus larvae, is the most serious brood disease. It occurs throughout the world wherever bees are kept and affects workers, drones, and queens. The spores are highly resistant to heat and chemicals. A ...
Bacillus mesentericus: (from the article "baking") Bacteria associated with bread spoilage include Bacillus mesentericus, responsible for "ropy" bread, and the less common but more spectacular Micrococcus prodigiosus, causative agent of "bleeding bread." Neither ropy bread nor bleeding bread is particularly toxic. Enzymes secreted by B. mesentericus ...
Bacillus polymyxa: (from the article "bacillus") ...thuringiensis insecticides are harmless to vertebrates but effective against pests of agricultural products. Medically useful antibiotics are produced by B. subtilis (bacitracin) and B. polymyxa (polymyxin B).
Bacillus popilliae: (from the article "Japanese beetle") ...to prey on the larvae-have been imported into the United States, where some of them have become established. Of even greater promise as a biological control is a disease-inducing bacterium, Bacillus popilliae, which causes milky disease in larvae; its use ...
Bacillus subtilis: (from the article "bacillus") Bacillus cereus sometimes causes spoilage in canned foods and food poisoning of short duration. B. subtilis, also widely disseminated, is a common contaminant of laboratory cultures (it plagued Louis Pasteur in many of his experiments) and is often found on ...
Bacillus thuringiensis: (from the article "bacillus") ...for humans and only infect them incidentally in their role as soil organisms; a notable exception is B. anthracis, which causes anthrax (q.v.) in humans and domestic animals. B. thuringiensis causes disease in insects; B. thuringiensis insecticides are harmless to ...
bacitracin: (from the article "drug") ...It has excellent activity against Pseudomonas aeruginosa and Enterobacteriaceae. Aztreonam has a low incidence of toxicity, but it must be administered parenterally. Bacitracin is produced by a special strain of Bacillus subtilis. Because of ...
back: (from the article "stringed instrument") In the lute the part of the resonating chamber over which the strings pass is called the belly, and the other side of the resonator is called the back. The portion between the back and belly is the side, or ...
back: (from the article "rugby") It was not until the early 1880s that specialized positions began to appear, particularly among the backs, with Allen Rotherham of Oxford and England establishing the position of halfback, named for a player who took up a position between the ...
Back Bay: (from the article "Mumbai") ...ridge terminates at Malabar Hill, which, rising 180 feet (55 metres) above sea level, is one of the highest points in Mumbai. Between Colaba Point and Malabar Hill lies the shallow expanse of Back Bay. On a slightly raised strip ...
Back Bay: (from the article "Boston") ...of land along the line of present-day Washington Street. To the west of the neck were great reaches of mudflats and salt marshes that were covered by water at high tide and known collectively as the Back Bay. The Charles ...
Back Bay: (from the article "Virginia Beach") ...extends 28 miles (45 km) southward from the mouth of Chesapeake Bay to the North Carolina border, covering 302 square miles (782 square km) of land and water, with 28 miles (45 km) of ocean front. Back Bay is a ...
back emf: (from the article "inductance") ...the increase of a current than the same coil with an air core. The iron core increases the inductance; for the same rate of change of the current in the coil, a greater opposing electromotive force (back emf) is present ...
back furrow: (from the article "agricultural technology") ...is plowed across the field; on the return trip, a furrow slice is lapped over the first slice. This leaves a slightly higher ridge than the second, third, and other slices. The ridge is called a back furrow. When two ...
back junction layer: (from the article "solar cell") The three energy-conversion layers below the antireflection layer are the top junction layer, the absorber layer, which constitutes the core of the device, and the back junction layer. Two additional electrical contact layers are needed to carry the electric current ...
back mutation: (from the article "heredity") ...against which to compare a mutant allele. Mutation can occur in two directions; mutation from wild type to mutant is called a forward mutation, and mutation from mutant to wild type is called a back mutation or reversion.
Back of the Yards Council: (from the article "Alinsky, Saul") ...and criminology, Alinsky worked as a criminologist in Illinois for eight years. In 1938, he undertook his first community organizing campaign in a working-class area of Chicago; the result was the Back of the Yards Council, which became a prototype ...
back pi bonding: (from the article "organometallic compound") ...The second mode of interaction with the metal is the simultaneous back-donation of electron density from the metal to the carbonyl ligand, which is called back pi bonding.
back projection: (from the article "projection screen") ...viewing angle increases). They are therefore especially suitable for screenings in small rooms-e.g., for home movies. The glass-beaded screen is made up of many tiny beads on a canvas backing, the lenticular screen of tiny, uniformly spaced, cylindrical lenses.use withmotion ...
back stroke: (from the article "cricket") ...stroke, in which the batsman advances his front leg to the pitch (direction) of the ball and plays it in front of the wicket (if played with aggressive intent, this stroke becomes the drive); back stroke, in which the batsman ...
back swimmer: any of about 200 species of insects (order Heteroptera) that occur worldwide and are named for their ability to swim on their backs, which are shaped like the keel and sides of a boat. The back swimmer uses its long, ... [2 Related Articles]
back vowel: (from the article "vowel") ...part of the tongue pushed forward in the mouth and somewhat arched. The a in "had," the e in "bed," and the i in "fit" are front vowels. A back vowel-e.g., the u in "rule" and the o in "pole"-is ...
Back, Kurt W.: (from the article "collective behaviour") ...to be closed down and fumigated because of reports of toxic insect bites-reports that could not subsequently be substantiated. The U.S. sociologist Alan C. Kerckhoff and the U.S. psychologist Kurt W. Back found that the crisis came after a period ...
Back, Sir George: naval officer who helped to trace the Arctic coastline of North America. He twice accompanied the British explorer John Franklin to Canada's Northwest Territories (1819-22 and 1825-27) and later conducted two expeditions of his own to the same region.
back-arc basin: (from the article "plate tectonics") Where both converging plates are oceanic, the margin of the older oceanic crust will be subducted because older oceanic crust is colder and therefore more dense. As the dense slab collapses into the asthenosphere, however, it also may "roll back" ...
back-formation: (from the article "English language") Back-formations and blends are becoming increasingly popular. Back-formation is the reverse of affixation, being the analogical creation of a new word from an existing word falsely assumed to be its derivative. For example, the verb "to edit" has been formed ...
back-propagating error correction: (from the article "perceptrons") ...and Wesley Clark of the Massachusetts Institute of Technology had applied to only two-layer networks so that the procedure could be applied to multilayer networks. Rosenblatt used the phrase "back-propagating error correction" to describe his method. The method, with substantial ...
back-propagation algorithm: (from the article "neural network") Two modifications of this simple feedforward neural network account for the growth of commercial applications. First, a network can be equipped with a feedback mechanism, known as a back-propagation algorithm, that enables it to adjust the connection weights back through ...
back-strap loom: (from the article "textile") ...known of the American Indian weavers, have used the simple two-bar vertical loom for several centuries to produce their beautiful rugs and blankets. A form of the horizontal two-bar loom was the back-strap loom, in which one bar was tied ...
backblocks farce: (from the article "Australia") ...dominated by the development of two genres: the bushranging film, as exemplified by The Story of the Kelly Gang (1906), which depicted the life of Ned Kelly; and the "backblocks" farce, a genre that satirized farming families ...
backboard: (from the article "basketball") ...deflect the ball to favour one side and hinder the other; in 1895 teams were urged to provide a 4-by-6-foot (1.2-by-1.8-metre) screen for the purpose of eliminating interference. Soon after, wooden backboards proved more suitable. Glass backboards were legalized by ...
Backbone Mountain: highest point in Maryland, U.S., reaching an elevation of 3,360 feet (1,024 metres). It is located on a ridge of the Allegheny and Appalachian mountains, located in Garrett county 12 miles (19 km) south of Oakland. The ridge is 35 ... [2 Related Articles]
Backbone Range: (from the article "Chugoku Range") The Chugoku Range consists of three landforms-the Backbone Range, the Kibi Plateau, and the Iwami Plateau. The Backbone Range constitutes a sharp divide between the Sea of Japan and the Inland Sea, broken only by the gorge of the Gono ...
backcross: the mating of a hybrid organism (offspring of genetically unlike parents) with one of its parents or with an organism genetically similar to the parent. The backcross is useful in genetics studies for isolating (separating out) certain characteristics in a ... [3 Related Articles]
Backer, Jacob: (from the article "Rembrandt van Rijn") ...seems to be the case, for instance, in his portrait of the famous, banned Remonstrant preacher Johannes Wtenbogaert (1577-1644), who was also portrayed by Michiel Janszoon van Miereveld and Jacob Adriaenszoon Backer.
backgammon: game played by moving counters on a board or table, the object of the game being a race to a goal, with the movement of the counters being controlled by the throw of two dice. Elements of chance and skill ... [2 Related Articles]
background extinction rate: (from the article "conservation") To discern the effect of modern human activity on the loss of species requires determining how fast species disappeared in the absence of that activity. Studies of marine fossils show that species last about 1-10 million years (see the table, ...
background matching: (from the article "concealing coloration") in animals, the use of biological coloration to mask location, identity, and movement, providing concealment from prey and protection from predators. Background matching is a type of concealment in which an organism avoids recognition by resembling its background in coloration, ...
backhander: (from the article "ice hockey") There are three common types of shots in hockey: the slap shot, the wrist shot, and the backhander. The slap shot has been timed at more than 100 miles an hour (160 km an hour). The slap shot differs from ...
Backhaus, Wilhelm: German pianist who was best known for his interpretation of the works of Ludwig van Beethoven.
backhoe: (from the article "mining") In certain cases placer material is most economically excavated with a shore-mounted dragline or backhoe and a floating (barge-mounted) concentrating plant. (The digging equipment may also be mounted on a separate barge or on the same barge as the plant.) ...
Backhuysen, Ludolf: Dutch painter, celebrated for his sea pieces.
backlight: (from the article "liquid crystal display") The backlight of LCDs typically accounts for more than 80 percent of the display's power consumption. For mobile complex displays, battery lifetime is of great importance, and clearly the development of products that can be viewed in ambient light without ...