Fr.: connecteur logique
A symbol that can be combined with one or more → sentences in order to form a new sentence. For example "and" (∧), "or" (∨) "not" (¬), "if-then" (→), and "iff" (⇔).
Fr.: logiquement équivalent
Fr.: identification, connexion
1) The act of logging in to a database, mobile device, or computer,
especially a multi-user computer or a remote or networked computer system.
Fr.: distribution logarithmico-normale
Fr.: fin de session, déconnexion
The process by which a computer user logs out.
Fr.: périodogramme de Lomb-Scargle
An algorithm for detecting and characterizing periodic signals in unevenly-sampled data. The Lomb-Scargle periodogram has a particularly wide use within the astronomy community. This method allows efficient computation of a Fourier-like → power spectrum estimator from such unevenly-sampled data, resulting in an intuitive means of determining the period of oscillation (see VanderPlas, 2017, astro-ph/1703.09824 and references therein).
Named after Lomb, N. R. 1976, Ap&SS 39, 447 and Scargle, J. D. 1982, ApJ 263, 835; → periodogram.
M.E. longe, O.E. lang, long, akin to O.H.G., Ger. lang "long," O.N. langr, M.Du. lanc, Goth. laggs "long," L. longus, → longitude.
Derâz "long," Mid.Pers. drâz "long;" O.Pers. darga- "long;" Av. darəga-, darəγa- "long," drājištəm "longest;" cf. Skt. dirghá- "lon (in space and time)."
domdâr-e derâz dowré
Fr.: comète à longue période
vartande-ye derâz dowré
Fr.: variable à longue période
The angular distance on the Earth's surface, measured east or west from the prime meridian at Greenwich to the meridian passing through a position, expressed in degrees (or hours), minutes, and seconds.
L. longitudo "length," from longus "long," cognate with Pers. derâz, as below, Gk. dolikhos "elongated;" O.H.G., Ger. lang, O.N. langr, M.Du. lanc, Goth. laggs "long;" PIE base *dlonghos- "long."
Derežnâ, from derež (Kurdi, Laki), variants darg "length; long, tall" (Zâzâ), darγ (Ossetic), derâz "long" + -nâ noun forming suffix from adjective, as in derâznâ, pah(n)nâ, farâxnâ, tangnâ, tiznâ. The first element from Mid.Pers. drâz "long;" O.Pers. darga- "long;" Av. darəga-, darəγa- "long," drājištəm "longest;" cf. Skt. dirghá- "lon (in space and time);" PIE *dlonghos- "long," as above.
longitude of ascending node
derežnâ-ye gereh-e farâzeši
Fr.: longitude du nœ ud ascendant
One of the → orbital elements used to specify the orbit of an object in space. It is the angle from the reference direction, called the origin of longitude, to the direction of the → ascending node, measured in the reference plane.
Of or pertaining to longitude or length. Extending in the direction of the length.
Adj. of → longitude.
longitudinal magnetic field
meydân-e meqnâtisi-ye derežnâyi
Fr.: champ magnétique longitudinal
1) A → magnetic field whose lines of force
(→ line of force)
run parallel to the long axis of the → magnet.
of a component can be accomplished using the longitudinal field set
up by a → coil or
→ solenoid. It can also be accomplished using
permanent magnets or electromagnets.
Fr.: masse longitudinale
In special relativity theory, the mass of a body when the acceleration is parallel or anti-parallel to velocity: ml = m0 / [1 - (v/c)2]3/2, where m0 is the → rest mass, v is the velocity, and c the → velocity of light. → transverse mass.
Fr.: onde longitudinale
longitudinal Zeeman effect
oskar-e Zeeman-e derežnâyi
Fr.: effet Zeeman longitudinal
The → Zeeman effect when the emitting source is viewed in the direction of the magnetic field. In the normal longitudinal effect, each spectral line is split into two components with frequencies ν ± Δν. The line with the frequency ν - Δν shows left-hand → circular polarization and that with frequency ν + Δν shows right-hand circular polarization. → transverse Zeeman effect.
The act or instance of looking.
Look, from W.Gmc. *lokjan (cf. O.S. lokon, M.Du. loeken, O.H.G. luogen, Ger. dialectal lugen "to look out"), of unknown origin.
Negâh "look," from Mid.Pers. nikâh "look, glance, observation;" Proto-Iranian *ni-kas- "to look down," from ni- "down," → ni- (PIE), + *kas- "to look, appear;" cf. Av. nikā-, nikāta- (in the name of the 15-th nask) "that which is observed," ākas- "to look;" Mid.Pers. âkâh, Mod.Pers. âgâh "aware, knowing;" Skt. kāś- "to become visible, appear;" Ossetic kast/kaesyn "to look."
zamân-e negâh bé gozašté
Fr.: temps de retour en arrière
The time that has elapsed since the light was emitted from a distant object (of → redshift z). Because → light moves at a → constant → speed, it takes a finite time to travel from distant objects. Hence, we "see" distant objects at a point in time in their past. In other words, look-back time is the difference between the age of the Universe now and the age of the Universe at the time the photons were emitted from the object. See also → comoving distance.
Zamân, → time; negâh, → look; gozašté "past, passed" (from gozaštan "to pass, proceed, go on," variant gozâštan "to put, to place, let, allow;" Mid.Pers. widardan, widâštan "to pass, to let pass (by);" O.Pers. vitar- "to pass across," viyatarayam "I put across;" Av. vi-tar- "to pass across," from vi- "apart, away from" (O.Pers. viy- "apart, away;" Av. vi- "apart, away;" cf. Skt. vi- "apart, asunder, away, out;" L. vitare "to avoid, turn aside") + O.Pers./Av. tar- "to cross over").
Anything shaped more or less like a loop, i.e. portion of a cord, ribbon, etc.,
folded or doubled upon itself.
Probably of Celtic origin (cf. Gael. lub "bend," Ir. lubiam), influenced by O.N. hlaup "a leap, run."
Gerdâl, from gerd "round, a circle" (Mid.Pers. girdag "disk, round," from gird/girt "round, all around," Proto-Iranian *gart- "to twist, to wreathe," cf. Skt krt "to twist threads, spin; to wind; to surround;" kata- "a twist of straw," Pali kata- "ring, bracelet," Gk. kartalos "a kind of basket," kyrtos "curved") + → -al.
Fr.: protubérance en boucle
A very bright active prominence in the form of a loop seen in Hα after a rather big flare. Also called "post-flare loops," they connect the feet where the two-ribbon flares were seen. The lifetime of loop prominences is several hours.