function csa = cshort(AF, m)
%cshort(AF, m)	Determines c for the short angle factors
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%AF = age factor = agefact(age)
%m = pigmentation parameter (see pigment)
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%Based on Ijspeert, et al. 1992.
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%SEE: c1calc, c2calc, clong

csa = (1 / (1 + (AF/(m^-1-1)))); %csa calculation