perilla oil, drying oil obtained from the seeds of Asiatic mint plants of the genus Perilla. Perilla oil is used along with synthetic resins in the production of varnishes. Perilla oil dries in less time than linseed oil and on drying forms a film that is harder and yellows more than that formed by

insurance: Perils clause: Until 1978 the main insuring clause of modern ocean marine policies was preserved almost unchanged from the original 1779 Lloyd’s of London form. The clause is as follows:

Pearl White: The Perils of Pauline was the most successful example of its genre—the short-episode serial that emphasized suspense, danger, and the cliff-hanger ending that aimed at bringing the audience back for the next sequel. The Perils of Pauline made White an international movie star whose fame…

human ear: Inner ear: …is the watery fluid called perilymph. It is derived from blood plasma and resembles but is not identical with the cerebrospinal fluid of the brain and the aqueous humour of the eye. Like most of the hollow organs, the membranous labyrinth is lined with epithelium (a sheet of specialized cells…

human ear: Structure of the cochlea: …aqueduct, through which passes the perilymphatic duct. This duct connects the interior of the cochlea with the subdural space in the posterior cranial fossa (the rear portion of the floor of the cranial cavity).

Perim Island, island in the Strait of Mandeb off the southwestern coast of Yemen, to which it belongs. A rocky volcanic island, lying just off the southwestern tip of the Arabian Peninsula, Perim is 5 square miles (13 square km) in area and rises as high as 214 feet (65 m). It has a harbour on the

menopause: Menopause and ovarian function: …a transitional phase known as perimenopause which can begin as early as 10 years before menopause, first some follicles and later all follicles fail to rupture and release their ova. In the last one or two years of perimenopause, estrogen levels decline quickly.

human eye: The visual field: …field is measured on a perimeter, a device for ascertaining the point on a given meridian where a white spot just appears or disappears from vision when moved along this meridian. (A meridian is a curve on the surface of a sphere that is formed by the intersection of the…

meat processing: Skeletal muscle structure: …tissue sheath known as the perimysium. Clusters of fat cells, small blood vessels (capillaries), and nerve branches are found in the region between muscle bundles. Muscle bundles are further divided into smaller cylindrical muscle fibres (cells) of varying lengths that are individually wrapped with a thin connective tissue sheath called…

Bob Jones University v. United States: The Supreme Court’s ruling: …its landmark 1861 decision in Perin v. Carey:

The Four Feathers: …by an outstanding cast and Georges Périnal’s sweeping colour cinematography. Among the many other film versions of the tale, with assorted variations, are a 1955 production (Storm over the Nile) featuring Laurence Harvey and directed by Korda and Terence Young (director of the early James Bond films) and a 2002…

infant and toddler health: Infant mortality: Perinatal (within the first month of life) mortality rates have also declined, due to improvements in medical knowledge and technology and increased attention paid to prenatal care and infant health. In addition, the incidences of low-birth-weight newborns and short-gestational births have dropped in some countries,…

human reproductive system: The scrotum: …is continued back onto the perineum (the area between the legs and as far back as the anus). This arrangement indicates the bilateral origin of the scrotum from two genital swellings that lie one on each side of the base of the phallus, the precursor of the penis or clitoris…

nervous system: Types of neuroglia: In gray matter, perineuronal oligodendrocytes are located in close proximity to the somata of neurons. In the peripheral nervous system, neuroglia that are equivalent to oligodendrocytes are called Schwann cells.

White House press secretary: Press secretaries in the 21st century: In 2007 Dana Perino replaced Snow, becoming the second woman to serve as press secretary.

Philip II: Presidency of the Thessalian League: …Greek allies, the cities of Perinthus (later called Heraclea, present-day Marmaraereğlisi) and Byzantium, to review their position, and his coercion of them led to the two great sieges that showed the development of his artillery and allied arms, of which his son Alexander was to make greater use in Asia.

Livy: Livy’s history of Rome: …of contents (known as the Periochae) of the whole work. A note in the Periochae of Book 121 records that that book (and presumably those that followed) was published after Augustus’ death in ad 14. The implication is that the last 20 books dealing with the events from the Battle…

period, in geology, the basic unit of the geologic time scale; during these spans of time specific systems of rocks were formed. Originally, the sequential nature of defining periods was a relative one, originating from the superposition of corresponding stratigraphic sequences and the evidence

punctuation: Punctuation in English since 1600: …full point, full stop, or period. The period may also be used to mark abbreviations. The colon (:), which was once used like a full point and was followed by an uppercase letter, now serves mainly to indicate the beginning of a list, summary, or quotation. The semicolon (;) ranks…

menstruation, periodic discharge from the vagina of blood, secretions, and disintegrating mucous membrane that had lined the uterus. The biological significance of the process in humans can best be explained by reference to the reproductive function in other mammals. In a number of species of wild

chemical bonding: Arrangement of the elements: The horizontal rows of the periodic table are called periods. Each period corresponds to the successive occupation of the orbitals in a valence shell of the atom, with the long periods corresponding to the occupation of the orbitals of a d subshell. Successive periods down the table correspond to successively…

period, in physics, the interval of time it takes for a motion to repeat. Such motion is called periodic motion and is performed, for example, by a rocking chair, a bouncing ball, a vibrating tuning fork, a swing in motion, Earth in its orbit around the Sun, and a water wave. Thus, the period of

period, in music, a unit of melodic organization made up of two balanced phrases in succession; the first phrase, called the antecedent, comes to a point of partial completeness; it is balanced by the consequent, a phrase of the same length that concludes with a sense of greater completeness. The

Jeffrey C. Hall: …of the period gene product, PER, fluctuated in the fruit fly brain, with PER building up at night and declining during the day. The oscillations, they discovered, were the result of a negative feedback loop, whereby PER was produced until it reached a specific level, at which point it then…

George Roy Hill: Film directing: Period of Adjustment (1962) was a light but pleasant romantic comedy starring Jane Fonda, Anthony Franciosa, and Jim Hutton, and Toys in the Attic (1963; based on Lillian Hellman’s drama) featured the unlikely cast of Dean Martin, Geraldine Page, and Wendy Hiller.

Russia: The lands of Rus: …often been called the “Period of Feudal Partition.” This phrase is misleading: feudal is hardly more applicable to the widely varying institutions of this time than to those of the Kievan period, and partition implies a former unity of which there is insufficient evidence. The distinctiveness of the character…

galaxy: The problem of the Magellanic Clouds: …he made use of the period-luminosity (P-L) relation discovered by Henrietta Leavitt of the Harvard College Observatory. In 1912 Leavitt had found that there was a close correlation between the periods of pulsation (variations in light) and the luminosities (intrinsic, or absolute, brightnesses) of a class of stars called Cepheid…

contraception: Fertility awareness techniques: Three procedures can be followed to predict ovulation so that, during the approximately six days of a woman’s most fertile monthly phase, sexual intercourse can be avoided. Their effectiveness is typically about 80 percent but may reach as high as 99 percent,…

space group, in crystallography, any of the ways in which the orientation of a crystal can be changed without seeming to change the position of its atoms. These changes may involve displacement of the whole structure along a crystallographic axis (translation), as well as the point group operations

reproductive behaviour: Natural selection and reproductive behaviour: …favourable rather than less favourable period will eventually dominate succeeding generations. This is the basis for the seasonality of reproduction among most animal species.

periodical cicada, (genus Magicicada), genus of seven species of cicadas known for their unusual highly synchronized life cycles and raucous choruses. Periodical cicadas are native to the eastern and midwestern United States but are not present aboveground every year. In what are among the longest

comet: General considerations: …after the name of a periodic comet denoted its order among comets discovered by that individual or group, but for new comets there would be no such distinguishing number.

election, the formal process of selecting a person for public office or of accepting or rejecting a political proposition by voting. It is important to distinguish between the form and the substance of elections. In some cases, electoral forms are present but the substance of an election is

trigonometry: Trigonometric functions of an angle: …that the trigonometric functions are periodic and have a period of 360° or 180°.

brick and tile: Firing and cooling: In so-called periodic kilns the bricks are placed with sufficient air space to allow the heat from the fires to reach all surfaces. They are placed directly from the drier, and heat is gradually increased until the optimum firing temperature is reached. When they are sufficiently fired,…

atom: Atomic weights and the periodic table: …paper of 1869 introducing the periodic law, he credited Cannizzaro for using “unshakeable and indubitable” methods to determine atomic weights.

periodic motion, in physics, motion repeated in equal intervals of time. Periodic motion is performed, for example, by a rocking chair, a bouncing ball, a vibrating tuning fork, a swing in motion, the Earth in its orbit around the Sun, and a water wave. In each case the interval of time for a

periodic paralysis, any of the forms of a rare disorder that is characterized by relatively short-term, recurrent attacks of muscle weakness. Usually the disorder is inherited; it occurs three times more often in males than in females. Hypokalemic paralysis (often referred to as familial) is caused

celestial mechanics: Examples of perturbations: …longitude of the node are periodic perturbations (periodically changing their direction), which are revealed by the fact that the rate of secular regression of the node is not constant in time. The Sun causes a secular increase in the longitude of the lunar perigee (Ω + ω in Figure 2)…

continental landform: The concept of periodic random dominance: The concept of periodic random dominance as an aspect of landform evolution carries with it the implication of polygenetic landforms and landscapes where geomorphic system dominance fails to develop. Indeed, dominance becomes the special case because it is dependent on a particular juxtaposition of tectonic and/or climatic elements…

periodic table, in chemistry, the organized array of all the chemical elements in order of increasing atomic number—i.e., the total number of protons in the atomic nucleus. When the chemical elements are thus arranged, there is a recurring pattern called the “periodic law” in their properties, in

periodic table, in chemistry, the organized array of all the chemical elements in order of increasing atomic number—i.e., the total number of protons in the atomic nucleus. When the chemical elements are thus arranged, there is a recurring pattern called the “periodic law” in their properties, in

The Periodic Table, collection of memoirs by Primo Levi, published in Italian as Il sistema periodico in 1975 and regarded as his masterwork. It is a cycle of 21 autobiographical stories, each named after and inspired by a chemical element. To Levi, who was a chemist as well as a writer, each

property law: Landlord and tenant: …before the term expires (periodic tenancy). Thus, tenancies can be arranged, for example, from week to week, month to month, or year to year. It is also possible to have a tenancy for no fixed term but subject simply to the will of the landlord and tenant (tenancy at…

magazine, a printed or digitally published collection of texts (essays, articles, stories, poems), often illustrated, that is produced at regular intervals (excluding newspapers). A brief treatment of magazines follows. For full treatment, see publishing: Magazine publishing. The modern magazine

periodical cicada, (genus Magicicada), genus of seven species of cicadas known for their unusual highly synchronized life cycles and raucous choruses. Periodical cicadas are native to the eastern and midwestern United States but are not present aboveground every year. In what are among the longest

rhythm: Theories requiring “periodicity” as the sine qua non of rhythm are opposed by theories that include in it even nonrecurrent configurations of movement, as in prose or plainchant.

sound: The ear as spectrum analyzer: This effect, known as the missing fundamental, subjective fundamental, or periodicity pitch, is used by the ear to create the fundamental in sound radiating from a small loudspeaker that is not capable of providing low frequencies.

reproductive behaviour: Natural selection and reproductive behaviour: …favourable rather than less favourable period will eventually dominate succeeding generations. This is the basis for the seasonality of reproduction among most animal species.

amorphous solid: Distinction between crystalline and amorphous solids: …property called long-range order or translational periodicity; positions repeat in space in a regular array, as in Figure 2A. In an amorphous solid, translational periodicity is absent. As indicated in Figure 2B, there is no long-range order. The atoms are not randomly distributed in space, however, as they are in…

periodontal membrane, fleshy tissue between tooth and tooth socket that holds the tooth in place, attaches it to the adjacent teeth, and enables it to resist the stresses of chewing. It develops from the follicular sac that surrounds the embryonic tooth during growth. The periodontal membrane

periodontal membrane, fleshy tissue between tooth and tooth socket that holds the tooth in place, attaches it to the adjacent teeth, and enables it to resist the stresses of chewing. It develops from the follicular sac that surrounds the embryonic tooth during growth. The periodontal membrane

periodontics, dental specialty concerned with the prevention, diagnosis, and treatment of functional and structural diseases of the periodontal membrane and related tissues that surround and support the teeth. Degeneration or inflammation of these tissues can be caused by various systemic or local

periodontitis, inflammation of the soft tissues around the teeth, characterized by swollen tender gums (gingivitis), that may lead to the eventual loss of teeth. Periodontitis begins with the deposition of bacterial plaque on the teeth below the gum line, irritating and eroding the neighboring

periodontal membrane, fleshy tissue between tooth and tooth socket that holds the tooth in place, attaches it to the adjacent teeth, and enables it to resist the stresses of chewing. It develops from the follicular sac that surrounds the embryonic tooth during growth. The periodontal membrane

sports: Crete and Greece: …events were known as the periodos, and great athletes, such as Theagenes of Thasos, prided themselves on victories at all four sites. Although most of the events contested at Greek sacred games remain familiar, the most important competition was the chariot race. The extraordinary prestige accorded athletic triumphs brought with…

Hecataeus of Miletus: …of the Periodos gēs or Periēgēsis (“Tour Round the World”); it was written in two parts—one covering Europe, the other “Asia” (which included Egypt and North Africa). The work describes the peoples who would be met in voyages around the Mediterranean and Black seas, in a clockwise direction, beginning with…

The history of American literature reaches from the oral traditions of Native peoples to the novels, poetry, and drama created in the United States today. This list describes its six major periods. list, American literature, Native American literature, periods, history, writing, authors, American

annelid: Regeneration: …obtained in an earthworm (Perionyx excavatus). A piece removed from the anterior end regenerates a head at both cut ends if the cuts are made simultaneously. If the new anterior head then is removed, the posterior head becomes dominant and evokes tail regeneration at the surface from which the…

periosteum, dense fibrous membrane covering the surfaces of bones, consisting of an outer fibrous layer and an inner cellular layer (cambium). The outer layer is composed mostly of collagen and contains nerve fibres that cause pain when the tissue is damaged. It also contains many blood vessels,

bivalve: The shell: The periostracum, the outermost organic layer, is secreted by the inner surface of the outer mantle fold at the mantle margin. It is a substrate upon which calcium carbonate can be deposited by the outer surface of the outer mantle fold. The number of calcareous layers…

Aristotle: The Lyceum of Aristotle: …brilliant research students, called “peripatetics” from the name of the cloister (peripatos) in which they walked and held their discussions. The Lyceum was not a private club like the Academy; many of the lectures there were open to the general public and given free of charge.

Lyceum, Athenian school founded by Aristotle in 335 bc in a grove sacred to Apollo Lyceius. Owing to his habit of walking about the grove while lecturing his students, the school and its students acquired the label of Peripatetics (Greek peri, “around,” and patein, “to walk”). The peripatos was the

velvet worm: A common genus is Peripatus, found in the West Indies, Central America, and the northern parts of South America. About 20 species of Peripatus are known. They have an elongated body consisting of 14 to 44 trunk segments, each having a pair of short legs. The number of segments…

peripeteia, the turning point in a drama after which the plot moves steadily to its denouement. It is discussed by Aristotle in the Poetics as the shift of the tragic protagonist’s fortune from good to bad, which is essential to the plot of a tragedy. It is often an ironic twist, as in Sophocles’

peripheral device, any of various devices (including sensors) used to enter information and instructions into a computer for storage or processing and to deliver the processed data to a human operator or, in some cases, a machine controlled by the computer. Such devices make up the peripheral

human ear: Auditory nerve fibres: …cochlear nerve, and the shorter, peripheral fibres extend to the bases of the inner and outer hair cells. They extend radially from the spiral ganglion to the habenula perforata, a series of tiny holes beneath the inner hair cells. At this point they lose their myelin sheaths and enter the…

AGP: …processing unit) and system memory—unlike PCI (peripheral component interconnect), an earlier graphics card standard on which AGP was based. In graphics-intense applications, this direct channel gave AGP a performance advantage over PCI, which had been used for graphics cards, network cards, and countless other devices.

AGP: …graphics technology about 2010 by PCI Express, a high-speed version of PCI that replaced both PCI and AGP.

peripheral device, any of various devices (including sensors) used to enter information and instructions into a computer for storage or processing and to deliver the processed data to a human operator or, in some cases, a machine controlled by the computer. Such devices make up the peripheral

Ranunculales: …and orders known as the peripheral eudicots. One of the main characteristics that distinguish these families and other eudicots from the monocotyledons (species with one embryonic leaf in their seed) and basal angiosperms is the pollen, which typically has three openings (colpi) instead of one. They also lack ethereal oils,…

peripheral immune tolerance, the set of mechanisms that prevent immune cells—especially T cells and B cells—from attacking the body’s own tissues after the cells have matured and left so-called central tolerance sites—namely, the thymus and bone marrow. By maintaining control over self-reactive

air-cushion machine: History: …system is known as a peripheral jet. Once air has built up below the craft to a pressure equaling the craft weight, incoming air has nowhere to go but outward and experiences a sharp change of velocity on striking the surface. The momentum of the peripheral jet air keeps the…

Romance languages: Classification methods and problems: …whereas French and Romanian are peripheral (they lack similarity to other Romance languages and require more effort for other Romance speakers to understand them).

spinal cord injury: Changing attitudes and therapeutic approaches: Specialized hospital units known as peripheral nerve centres, which had been developed in the time between the two World Wars, demonstrated the advantages of delivering tailored care to special-needs patients. Great importance was attributed to the unique opportunities offered by such specialized units, particularly their ability to offer new insight…

human nervous system: The peripheral nervous system: The peripheral nervous system is a channel for the relay of sensory and motor impulses between the central nervous system on one hand and the body surface, skeletal muscles, and internal organs on the other hand. It is composed of (1) spinal…

alcoholism: Acute diseases: …alcoholism can also lead to polyneuropathy, a degenerative disease of the peripheral nerves with symptoms that include tenderness of calf muscles, diminished tendon reflexes, and loss of vibratory sensation. Inflammation and fatty infiltration of the liver are common, as are disorders of the gastrointestinal tract (gastritis, duodenal ulcer, and, less…

cell membrane: Composition: 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…

pump: Kinetic pumps.: A regenerative pump is also called a turbine, or peripheral, pump. The impeller has vanes on both sides of the rim that rotate in a ringlike channel in the pump’s casing. The fluid does not discharge freely from the tip of the impeller but is recirculated…

William Gibson: The Peripheral (2014) investigates the possibility of communication with future societies by way of computer technology. Its prequel/sequel, Agency, was published in 2020.

periphrasis, the use of a longer phrasing in place of a possible shorter form of expression; a roundabout or indirect manner of writing or speaking. In literature periphrasis is sometimes used for comic effect, as illustrated by Charles Dickens in the speech of the character Wilkins Micawber, who

Platonism: Medieval Platonism: …the Periphyseon (usually known as De divisione naturae [On the Division of Nature]), was not much read and ceased to be copied after his condemnation in 1210. But a considerable part of the text circulated in the form of anonymous glosses to the Latin translations of the Pseudo-Dionysius (of which…

inland water ecosystem: Population and community development and structure: …in the water column); the periphyton (microscopic biota on submerged objects); the psammon (biota buried in sediments); and the neuston (biota associated with surface film). These organisms differ enormously in size, ranging from less than 0.5 micrometre (0.00002 inch) to greater than 1 metre (3.28 feet). They also vary in…

inland water ecosystem: Population and community development and structure: …in the water column); the periphyton (microscopic biota on submerged objects); the psammon (biota buried in sediments); and the neuston (biota associated with surface film). These organisms differ enormously in size, ranging from less than 0.5 micrometre (0.00002 inch) to greater than 1 metre (3.28 feet). They also vary in…

cockroach: Family Blattidae: The American cockroach (Periplaneta americana), a native of Africa and the Middle East, is 30 to 50 mm (1.2−2 inches) long, is reddish brown, and lives outdoors or in dark heated indoor areas (e.g., basements and furnace rooms). During adult life, a period of about 1.5…

navigation: Sailing instructions: …to coastal navigation was the pilot book, or periplus, in which the courses to be steered between ports were set forth in terms of wind directions. These books, of which examples survive from the 4th century bc, described routes, headlands, landmarks, anchorages, currents, and port entrances. No doubt the same…

history of Arabia: Ḥimyarites: …known to scholars as the Periplus Maris Erythraei mentions an individual who was “king of two nations, the Homerites and the Sabaeans.” But this dual kingship was not definitive: throughout the 2nd and 3rd centuries there were phases of warfare between native Sabaean rulers and Ḥimyarite ones. Royal titulature in…

José Joaquín Fernández de Lizardi: His El periquillo sarniento (1816; The Itching Parrot), the first picaresque novel of Spanish America, is a colourful tale that depicts the state of Mexican society in the early 19th century and reflects the ideas of the French Enlightenment and of Jean-Jacques Rousseau on education. He also wrote La Quijotita…

chemoreception: Cellular mechanisms in chemoreception: …bathed; these are known as perireceptor events. Second, the molecule must interact with the surface of the receptor cell in a specific way to produce reactions within the cell. These reactions lead to a change in cellular electrical charge, which generates a nerve impulse. Transformation of an external stimulus into…

periscope, optical instrument used in land and sea warfare, submarine navigation, and elsewhere to enable an observer to see his surroundings while remaining under cover, behind armour, or submerged. A periscope includes two mirrors or reflecting prisms to change the direction of the light coming

jay: The gray jay (Perisoreus canadensis) inhabits the northern reaches of the United States and most of Canada.

seed: Angiosperm seeds: …derived from the nucellus, the perisperm, as in coffee. Other seeds, such as those of beets, contain both perisperm and endosperm. The seed coat, or testa, is derived from the one or two protective integuments of the ovule. The ovary, in the simplest case, develops into a fruit. In many…

perissodactyl, any member of the order Perissodactyla, a group of herbivorous mammals characterized by the possession of either one or three hoofed toes on each hindfoot. They include the horses, asses, and zebras, the tapirs, and the rhinoceroses. The name—from Greek perissos, “odd,” and daktylos,

perissodactyl, any member of the order Perissodactyla, a group of herbivorous mammals characterized by the possession of either one or three hoofed toes on each hindfoot. They include the horses, asses, and zebras, the tapirs, and the rhinoceroses. The name—from Greek perissos, “odd,” and daktylos,

peristalsis, involuntary movements of the longitudinal and circular muscles, primarily in the digestive tract but occasionally in other hollow tubes of the body, that occur in progressive wavelike contractions. Peristaltic waves occur in the esophagus, stomach, and intestines. The waves can be

peristalsis, involuntary movements of the longitudinal and circular muscles, primarily in the digestive tract but occasionally in other hollow tubes of the body, that occur in progressive wavelike contractions. Peristaltic waves occur in the esophagus, stomach, and intestines. The waves can be

circulatory system: Hearts: This type of heart is widely found among invertebrates, and there may be many pulsating vessels in a single individual.

locomotion: Bottom locomotion: Peristaltic locomotion is a common locomotor pattern in elongated, soft-bodied invertebrates, particularly in segmented worms, such as earthworms. It involves the alternation of circular- and longitudinal-muscle-contraction waves. Forward movement is produced by contraction of the circular muscles, which extends or elongates the body; contraction of…

scorpaeniform: Annotated classification: Family Peristediidae (armoured gurnards and armoured sea robins) Characterized by rather slender form, body and tail with large bony scutes; head heavily armoured. 2 lower pectoral fin rays separate. Large barbels on lower jaw. Deep benthic marine fishes from 200 to 500 metres (660 to 1,650…

Prudentius: The Peristephanon (“Crowns of Martyrdom”) contains 14 lyric poems on Spanish and Roman martyrs. Three long didactic poems give a polemical exposition of Christian doctrine in a form agreeable to those steeped in the old classical literary tradition. The Apotheosis is directed against disclaimers of the…