The condition or quality of being earlier in time or occurrence, or being regarded as more important.
1) General: The quality or fact of being probable. A strong
→ likelihood or chance of something.
Fr.: courbe de probabilité
A curve that describes the distribution of probability over the values of a random variable.
probability density function
karyâ-ye cagâli-ye šavânâyi
Fr.: fonction de densité de probabilité
A mathematical function whose integral over any interval gives the probability that a continuous → random variable has values in this interval. Also known as → density function, frequency function, → probability function.
Fr.: distribution de probabilité
The function that describes the range of possible values that a random variable can attain and the probability that the value of the random variable is within any (measurable) subset of that range.
Fr.: fonction de probabilité
A function that represents a probability distribution in terms of integrals. Also called probability density function or density function.
Fr.: théorie des probabilités
A branch of → mathematics with its own axioms and methods, which is based on the concept of → randomness and is concerned with the possible outcome of given → events and their relative → likelihoods and → distributions.
projected rotational velocity
tondâ-ye carxeši-ye farâšândé
Fr.: vitesse rotationnelle projetée
The → angular velocity of a star deduced from the → rotational broadening of its → spectral lines. It is expressed as v sini, where i is the → inclination of the rotational axis with respect to the normal to the → plane of the sky. The real equatorial rotational velocity can be determined only if the inclination of the rotational axis is known.
Math.: A relationship bewteen two quantities such that if one quantity changes the other changes in the same proportion; denoted as y ∝ x.
Fr.: constante de proportionalité
1) Extensive mention in the news media or by word of mouth or other means of communication.
Fr.: instabilitÃ© pulsationnelle
A term used to describe irregularly spaced, fine-scale structure in optically thick rings. The process relies on a combination of viscosity and self-gravity of ring material to produce this fine structure. Also known as overstability (Ellis et al., 2007, Planetary Ring Systems, Springer).
pulsational pair-instability supernova
abar-novâ-ye nâpâydâri-ye tapeši-ye joft, abar-now-axtar-e ~ ~ ~
Fr.: supernova à instabilité pulsationnelle de paires
A → supernova resulting from the → pair instability that generates several successive explosions. According to models, a first pulse ejects many solar masses of hydrogen layers as a shell. After the first explosion, the remaining core contracts and searches for a stable burning state. When the next explosion occurs a few years later, several solar masses of material are again ejected, which collide with the earlier ejecta. This collision can radiate 1050 erg of light, about a factor of ten more than an ordinary → core-collapse supernova. After each pulse, the remaining core contracts, radiates neutrinos and light, and searches again for a stable burning state. Later ejections have lower mass, but have higher energy. They quickly catch up with the first shell, where the collision dissipates most of their kinetic energy as radiation. The first SNe from → Population III stars are likely due to pulsational pair instability (Woosley et al. 2007, Nature 450, 390). See also → pair-instability supernova.
The degree to which → impurity is incorporated into a semiconductor material.
M.E., from O.Fr. pureté, from L.L. puritatem (nom. puritas) "cleanness, pureness," from purus "clean;" cf. Av. pūitika- "serving for purification," Mod.Pers. pâk "clean;" Skt. pavi- "to become clean," pávate "purifies, cleanses;" O.H.G. fouwen, fewen "to sift;" PIE base *peu- "to purify, cleanse."
Žâvi, noun from adj. žâv "pure."
cunâ (#), cuni (#)
M.E. qualite, from O.Fr. qualite (Fr. qualité), from L. qualitas, from qual(is) "of what sort?" + → -ity.
Cunâ, cuni, from Mid.Pers. cigôn "how?," cigônêh "nature, character," O.Pers/Av. ci- "what, any," collateral stem to ka- "who?, what?" (cf. Skt. ka-; Gk. po-; L. quo-; E. what, who; PIE *qwos/*qwes) + Av. gaona- "color" (Mid.Pers. gônak "kind, species").
candâ (#), candi (#)
The property of magnitude.
M.E., from rom O.Fr. quantite (Fr. quantité), from L. quantitatem (nominative quantitas), from quant(us) "how much?" + -itas, → -ity.
Candâ, candi "quantity," Mid.Pers. candih "amount, quantity," from cand "how many, how much; so many, much;" O.Pers. yāvā "as long as;" Av. yauuant- [adj.] "how great?, how much?, how many?," yauuat [adv.] "as much as, as far as;" cf. Skt. yāvant- "how big, how much;" Gk. heos "as long as, until."
Fr.: gravité quantique
A theory of gravity, yet to be developed, that would properly include quantum mechanics. Because of the tensor nature of general relativity, it is not renormalizable as a field theory in perturbation from flat space. So far various attempts to quantize general relativity have been unsuccessful.
Fr.: unitarité quantique
A property in → quantum mechanics whereby in a quantum system the sum of all probabilities of all possible outcomes must be 1. Quantum unitarity makes the modulous of a → quantum state invariant with time.
Fr.: vitesse radiale
The component of a three-dimensional velocity vector of an object directed along the line of sight. It is measured by examining the Doppler shift of lines in the spectrum of astronomical objects.
radial velocity curve
xam-e tondâ-ye šo'â'i
Fr.: courbe de vitesse radiale
A curve describing the variation of the radial velocity of a star, due to the Doppler effect, under the gravitational effect of a secondary body (companion or exoplanet). The amplitude of these variations depends upon the mass of the secondary and its distance from the star.