Glosario Circadiano

glosario circadiano



A
Acclimation n. A process consisting of physiological or behavioral changes occurring within the lifetime of an organism that reduce the strain caused by experimentally-induced changes in particular climatic factors such as ambient temperature and photoperiod. // v. = acclimate // adj. = acclimated. // Cf. Acclimatization and Adaptation.

Acclimatization n. Aprocess consisting of physiological or behavioral changes occurring within the lifetime of an organism that reduce the strain caused by the naturally-occurring changes in climatic factors associated with the seasons. // v. = acclimatize // adj. = acclimatized. // Cf. Acclimation and Adaptation.

Acrophase n. The time at which the peak of a rhythm occurs. Note: Originally, acrophase referred to thephase angle of the peak of a cosine wave fitted to the raw data of a rhythm (time series). When the term is applied to the actual rhythm, the acrophase will likely vary from cycle to cycle. Unit of measurement: hours (h) or degrees of circumference (°) in relation to an absolute or arbitrary reference. Caveat: The official units of time and of plane angle in the International System of Units are,respectively, the second and the radian. // Cf. Cosinor and Peak.

Action spectrum n. A function relating the effect of electromagnetic radiation to the wavelength of the radiation. // pl. = action spectra.

Actogram n. The graphical display of a time series along two time axes. The duration of a cycle (or predicted duration of a cycle) determines the length of each plot line. Successive cyclesare plotted on successive lines. Note: On each line, values may be plotted in digital format (all-or-none data points) or analog format (using compressed Y axes). // Cf. Cartesian plot.

Adaptation n. 1. A decrease in the responsiveness of a sensory mechanism resulting from previous or continuing stimulation. 2. A process consisting of physiological or behavioral changes, occurring within thelifetime of an organism or as a result of genetic selection in a species, that reduce the strain caused by climatic or non-climatic changes in the environment. // v. = adapt // adj. = adaptive, adapted, adaptable.

Ad libitum adj. Freely available. // adv. = ad libitum. // Abbreviation: ad lib.

After-effects n. pl. Characteristics of a rhythm that result from previous stimulation, such as thelonger free-running period observed after entrainment by a zeitgeber with period longer than that of the organism.

Alpha n. 1. The segment of a circadian cycle during which the organism is active. 2. The level of significance of a statistical test. // Cf. Rho.

Amplitude n. The difference between the peak (or trough) and the mean value of a wave. Note: For symmetrical waves, the amplitude ishalf the value of the range of oscillation. // Cf. Range of oscillation.

Anticipatory activity n. Activity exhibited prior to the initiation of a stimulus that is believed to be responsible for the activity. Note: In circadian physiology, the term anticipatory can be misleading. The organism's activity anticipates (precedes) the presentation of the synchronizing stimulus. However, there is noevidence that the anticipation is a volitional psychological state distinct from the phase angle of entrainment determined by the properties of the pacemaker and the zeitgeber.

Arrhythmia n. Absence of rhythmicity in a process that is normally rhythmic. // adj. = arrhythmic.

Astronomical time n. A standard of time based on astronomical observations. // Cf. Atomic time, Solar time, and Siderealtime.

Atomic time n. A standard of time based on the number of oscillations of the cesium-133 atom as its electrons move from high to low energy levels. Unit of measurement: second (s). // Cf. Astronomical time and Second.



B
Bathyphase n. The time at which the trough of a rhythm occurs. Note: This term is very rarely used. Unit of measurement: hours (h) or degrees of circumference (°)...