Glossary
For an extensive list of chronobiology related terms and definitions, please refer to Aschoff et al. (1965) and Marques & Oda (2012).
- Chronotype
- Any kind of temporal phenotype (Ehret, 1974; Pittendrigh, 1993). Usually, it refers to circadian phenotypes in a spectrum that goes from morningness to eveningness (Roenneberg et al., 2003). It can also be seen as an organism’s phase of entrainment (Roenneberg et al., 2012).
- Circadian rhythm
- A rhythm with a period close to a day/24h, an approximation to the period of the earth’s rotation (Pittendrigh, 1960). From the Latin circā, around, and dĭes, day (Latinitium, n.d.). Example: the sleep-wake cycle.
- Complex system
- There are several definitions. Here are some that I found to be of use:
- “Systems that don’t yield to compact forms of representation or description” (David Krakauer apud Mitchell (2013));
- “A system of many interacting parts where the system is more than just the sum of its parts” (Mark Newman apud Mitchell (2013));
- Systems with many connected agents that interact and exhibit self-organization and emergence behavior, all without the need for a central controller (adapted from Camilo Rodrigues Neto’s definition, supervisor of this thesis);
- Dialectics at its finest (my working definition).
- Entrainment
- A shift and alignment of biological rhythms induced by a zeitgeber input (Kuhlman et al., 2018). For example: a shift/alignment of an organism’s circadian rhythm when exposed to light.
- Infradian rhythm
- A rhythm with a period greater than a day/24h. From the Latin infrā, below (think in terms of period repetition), and dĭes, day (Latinitium, n.d.). Example: the menstrual cycle.
- Period
- Cycle duration of an oscillation. In a more technical way, the duration between two identical and consecutive phases in an oscillation (Kuhlman et al., 2018).
- System theory
- Two definitions can be of use:
- Science or discipline that investigates models, principles, and laws that are valid to systems in general (Bertalanffy, 1968);
- “The attempt of a reductionist scientific tradition to come to terms with complexity, nonlinearity, and change through sophisticated mathematical and computational techniques, a groping toward a more dialectical understanding that is held back by its philosophical biases and the institutional and economic contexts of its development” (Levins, 1998).
- Ultradian rhythm
- A rhythm with a period below a day/24h. From the Latin ultrā, beyond (think in terms of period repetition), and dĭes, day (Latinitium, n.d.). Example: the cardiac cycle.
- Zeitgeber
- Any periodic environmental signal/cue that can influence or regulate biological rhythms. From the German zeit, time, and geber, donor (Cambridge University Press, n.d.). Two main and well known zeitgebers are light exposure and environment temperature (Pittendrigh, 1960).