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  2. Photosynthetically active radiation - Wikipedia

    en.wikipedia.org/wiki/Photosynthetically_active...

    Radiation reaching a plant contains entropy as well as energy, and combining those two concepts the exergy can be determined. This sort of analysis is known as exergy analysis or second law analysis, and the exergy represents a measure of the useful work, i.e., the useful part of radiation which can be transformed into other forms of energy.

  3. Environmental radioactivity - Wikipedia

    en.wikipedia.org/wiki/Environmental_radioactivity

    The level of beryllium-7 in the air is related to the Sun spot cycle, as radiation from the Sun forms this radioisotope in the atmosphere. The rate at which it is transferred from the air to the ground is controlled in part by the weather.

  4. Photosynthesis - Wikipedia

    en.wikipedia.org/wiki/Photosynthesis

    The latter occurs not only in plants but also in animals when the carbon and energy from plants is passed through a food chain. The fixation or reduction of carbon dioxide is a process in which carbon dioxide combines with a five-carbon sugar , ribulose 1,5-bisphosphate , to yield two molecules of a three-carbon compound, glycerate 3-phosphate ...

  5. Plant physiology - Wikipedia

    en.wikipedia.org/wiki/Plant_physiology

    A germination rate experiment. Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants. [1]Plant physiologists study fundamental processes of plants, such as photosynthesis, respiration, plant nutrition, plant hormone functions, tropisms, nastic movements, photoperiodism, photomorphogenesis, circadian rhythms, environmental stress physiology, seed ...

  6. Greenhouse effect - Wikipedia

    en.wikipedia.org/wiki/Greenhouse_effect

    Radiation heat flow occurs in the direction from the surface to the atmosphere and space, [6] as is to be expected given that the surface is warmer than the atmosphere and space. While greenhouse gases emit thermal radiation downward to the surface, this is part of the normal process of radiation heat transfer. [77]

  7. Radiation - Wikipedia

    en.wikipedia.org/wiki/Radiation

    Thermal radiation is a common synonym for infrared radiation emitted by objects at temperatures often encountered on Earth. Thermal radiation refers not only to the radiation itself, but also the process by which the surface of an object radiates its thermal energy in the form of black-body radiation. Infrared or red radiation from a common ...

  8. Radioactive contamination - Wikipedia

    en.wikipedia.org/wiki/Radioactive_contamination

    Radioactive contamination can be due to a variety of causes. It may occur due to the release of radioactive gases, liquids or particles. For example, if a radionuclide used in nuclear medicine is spilled (accidentally or, as in the case of the Goiânia accident, through ignorance), the material could be spread by people as they walk around.

  9. Fractionation of carbon isotopes in oxygenic photosynthesis

    en.wikipedia.org/wiki/Fractionation_of_carbon...

    Carbon on Earth naturally occurs in two stable isotopes, with 98.9% in the form of 12 C and 1.1% in 13 C. [1] [8] The ratio between these isotopes varies in biological organisms due to metabolic processes that selectively use one carbon isotope over the other, or "fractionate" carbon through kinetic or thermodynamic effects. [1]