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  2. Lunar phase - Wikipedia

    en.wikipedia.org/wiki/Lunar_phase

    Each complete cycle of phases is called a "lunation". [7] The approximate age of the Moon, and hence the approximate phase, can be calculated for any date by calculating the number of days since a known new moon (such as 1 January 1900 or 11 August 1999) and reducing this modulo 29.53059 days (the mean length of a synodic month).

  3. Transtheoretical model - Wikipedia

    en.wikipedia.org/wiki/Transtheoretical_model

    The transtheoretical model is also known by the abbreviation "TTM" [2] and sometimes by the term "stages of change", [3] although this latter term is a synecdoche since the stages of change are only one part of the model along with processes of change, levels of change, etc. [1] [4] Several self-help books—Changing for Good (1994), [5 ...

  4. Phase transition - Wikipedia

    en.wikipedia.org/wiki/Phase_transition

    In physics, chemistry, and other related fields like biology, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic states of matter : solid , liquid , and gas , and in rare cases, plasma .

  5. Phase (waves) - Wikipedia

    en.wikipedia.org/wiki/Phase_(waves)

    Conversely, a phase reversal or phase inversion implies a 180-degree phase shift. [ 2 ] When the phase difference φ ( t ) {\displaystyle \varphi (t)} is a quarter of turn (a right angle, +90° = π/2 or −90° = 270° = −π/2 = 3π/2 ), sinusoidal signals are sometimes said to be in quadrature , e.g., in-phase and quadrature components of a ...

  6. Thermodynamic cycle - Wikipedia

    en.wikipedia.org/wiki/Thermodynamic_cycle

    Whether carried out reversible or irreversibly, the net entropy change of the system is zero, as entropy is a state function. During a closed cycle, the system returns to its original thermodynamic state of temperature and pressure. Process quantities (or path quantities), such as heat and work are process dependent.

  7. Cell cycle - Wikipedia

    en.wikipedia.org/wiki/Cell_cycle

    The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.

  8. Social cycle theory - Wikipedia

    en.wikipedia.org/wiki/Social_cycle_theory

    The long cycle, according to Dr. Dan Cox, is a period of time lasting approximately 70 to 100 years. At the end of that period, "the title of most powerful nation in the world switches hands." [15] Modelski divides the long cycle into four phases. When periods of global war, which could last as much as one-fourth of the total long cycle, are ...

  9. List of periods and events in climate history - Wikipedia

    en.wikipedia.org/wiki/List_of_periods_and_events...

    500 million years of climate change Ice core data for the past 400,000 years, with the present at right. Note length of glacial cycles averages ~100,000 years. Blue curve is temperature, green curve is CO 2, and red curve is windblown glacial dust (loess). Scale: Millions of years before present, earlier dates approximate.