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Fr.: équation personnelle
A systematic observational error due to the characteristics of the observer.
The sum total of the physical, mental, emotional, and social characteristics of an individual (Dictionary.com).
1) tanumidan; 2) tanumârdan
Fr.: 1) personnaliser; 2) personnifier
1) The attribution of human nature or character to animals, inanimate objects, or
abstract notions, especially as a rhetorical figure.
Verbal noun of → personify.
1) To conceive of or represent as a person or as having human qualities or powers.
A body of persons employed in an organization or place of work (Dictionary.com).
From Fr. personnel (as contrasted with matériel), from O.Fr. personel, → personal.
Tanumgân, from tanum, → personal, + -gân multiplicity suffix.
1) pargâsmandi, pargâsik; 2) pargâsmand, pargâsik
1) The technique or art of drawing three-dimensional objects on a flat surface so that
to give the right impression of their relative sizes and distances. A drawing so made.
From M.Fr. perspective, from M.L. (ars) perspectiva "science of optics," from feminine of perspectivus "of sight, optical" from L. perspectus, p.p. of perspicere "to inspect, look through," from → per- "through" + specere "to look at," → prospect.
O.Fr. perturber, from L. perturbare "to confuse, disorder, disturb," from per- "through" + turbare "disturb, confuse," from turba "turmoil, crowd," turbidus "muddy, full of confusion."
Parturidan, from par-, related to pirâ- (cf. Av. per- "to pass across, through") + turidan "to run away, be very much ashamed," tur "withdrawal, flight;" Lori, Laki tur "restive, disobedient," Laki turyâyen "to get angry, lose one's temper," probably cognate with L. turba, as above.
1) Any departure introduced into a steady state of a system.
The magnitude is often assumed to be small so
that the resulting terms in the dependent variables may be neglected.
The term "perturbation" is therefore sometimes used as synonymous with "small perturbation."
Verbal noun of → perturb.
Fr.: équation de perturbation
Any equation governing the behavior of a → perturbation.
Fr.: méthode de perturbation
Approximate method of solving a difficult problem if the equations to be solved depart only slightly from those of a problem already solved.
Fr.: corps perturbateur
A celestial body that causes a perturbation in the orbit of another body.
A prefix denoting 1015.
Of unknown origin.
A combining form meaning "rock," "stone." Also, petri-, and petr- when before a vowel.
From Gk. petro-, combining form of petra "rock."
Sang "rock," → stone.
Natural mixture of liquid hydrocarbons and other organic compounds that include crude oil, refined products obtained from the processing of crude oil, and natural gas liquids.
M.L. petroleum literally "rock oil," from L. petra "rock," from Gk. → petro-, + oleum "oil."
Naft, from Mid.Pers. npt "moist, damp; naphtha," nmb "moisture," from which derives Mod.Pers. nam "humidity, moisture;" Av. napta- "moist," nabah- "cloud; sky;" cf. Skt. nábhas- "moisture, cloud, mist;" PIE base *nebh- "cloud, vapor, fog, moist, sky" (Gk. nephos "cloud, mass of clouds," nephele "cloud;" L. nebula "mist," nimbus "rainstorm, rain cloud;" O.H.G. nebul; Ger. Nebel "fog;" O.E. nifol "dark"). The link between "water, moisture" and "naphta" is suggested to be the natural gas or oil seepages surfacing through water. In fact many of the Zoroastrian fire-temples were located in areas which contained large petroleum leakages, such as those in Khuzestân and at Surakhany near Baku.
An astrophysical source which accelerates → cosmic rays up to energies of several petaelectronvolts. For example, in the → Galactic center, cosmic ray → protons reach such energies. The source of such particles is a matter of research (→ HESS collaboration, 2016, Nature 531, 476).
Fr.: série de Pfund
A series of lines in the infrared spectrum of atomic hydrogen whose representing transitions between the fifth energy level and higher levels.
After August Herman Pfund (1879-1949), an American physicist and spectroscopist; → series.
PG 1159 star
Fr.: PG 1159
A member of the class of stars in transition between → post-AGB and → white dwarf stars, with temperatures as high as 200,000 K, mean mass about 0.6 Msun, and log g = 5.5-8. PG 1159 stars have no hydrogen or He I lines in their spectra, but do show weak He II lines and stronger lines of ionized carbon and oxygen. These stars are thought to be the exposed inner core of a star that has exploded as a → planetary nebula and is on its way to become a white dwarf. Also called → pre-degenerate star
Named after their prototype PG 1159-035, from the Palomar-Green Catalog of Ultraviolet Excess Stellar Objects (Green et al. 1986, ApJS 61, 305); → star.
Fr.: potentiel hydrogÃ¨ne
A → logarithmic measure of → hydrogen ion concentration, originally defined pH = log10 (1/[H+]), where [H+] is the concentration of hydrogen ions in → moles per liter of solution. The hydrogen ion concentration in pure water around room temperature is about 1.0 × 10-7 moles. Therefore, a pH of 7 is considered "neutral," because the concentration of hydrogen ions is exactly equal to the concentration of → hydroxide (OH-) ions produced by → dissociation of the → water. Increasing the concentration of hydrogen ions above 1.0 × 10-7 moles produces a solution with a pH of less than 7, and the solution is considered → acidic. Decreasing the concentration below 1.0 × 10-7 moles produces a solution with a pH above 7, and the solution is considered → alkaline or → basic. The neutral pH is different for each → solvent. For example, the concentration of hydrogen ions in pure ethanol is about 1.58 × 10-10 moles, so ethanol is neutral at pH 9.8. A solution with a pH of 8 would be considered acidic in ethanol, but basic in water.
From Ger. PH, introduced by Danish biochemist S.P.L. SÃ¸rensen (1868-1939) in 1909, from P, for Ger. Potenz "power, potency," and H, symbol of → hydrogen.