Function Description
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	Name: Z_M_MELT 
	Function: Pierre Lavigne's monomer melt function
	Parameters: a0 a1 a2 a3 a4 a5 a6

Notes
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M_MELT: model to fit temperature denaturation of a monomeric protein
monitored with circular dichroism.

NOTE: The temperature must be in Celcius

See Lavigne et al. 1998. J. Mol. Biol. 281, 165-

a0= mean residue ellipticity for the N state @ 0oC 
a1= constant slope for the temperature dependance 
    of the mean residue ellipticity of the N state
a2= mean residue ellipticity for the N state @ 0oC  
a3= constant slope for the temperature dependance 
	    of the mean residue ellipticity of the N state
a4= DHu (kcal/mol) 
a5= DCp,u (temperature independent, kcal/K mol)
a6= Tm (K)

C-code for the function
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b = x + 273.15;
c = b *((a[4] / a[6]) + a[5] * log(b / a[6]));
d = a[4] + a[5] * (b - a[6]);
e = (d - c) / 0.001987;
f = exp((-e) / b);
g = f / (1 + f);
answer = (1 - g) * (a[0] - a[1] * x) + g * (a[2] - a[3] * x);