Mole (unit) and growth chamber lighting for plants is sometimes expressed in micromoles per square meter per second, where 1 mol photons = photons. In 2011, the 24th meeting of the General Conference on Weights and Measures (CGPM) agreed to a plan for a possible revision of the SI base unit definitions at an undetermined date. The 26th meeting of the CGPM, in a formal vote on 16 November 2018, approved the proposed redefinition of SI base units mole, kilogram, ampere and kelvin. One mole of a substance will have exactly specified "elementary entities" of that substance. The definition of the mole
Cartan formalism (physics) the normal Einstein–Hilbert action, using the relations formula_95 and formula_96. Note that in terms of the Planck mass, we set formula_97, whereas the last term keeps all the SI unit factors. Note that in the presence of spinor fields, the Palatini action implies that formula_98 is nonzero. So there's a non-zero torsion, i.e. that formula_99. See Einstein–Cartan theory. Cartan formalism (physics) The vierbein or tetrad theory much used in theoretical physics is a special case of the application of Cartan connection in four-dimensional manifolds. It applies to metrics of any signature. (See metric tensor.) This section is an approach to