Memchord

$D_{Memchord} = \sqrt{ \sum_{j=1}^{S_T} \left ( \frac{S_{Aj}}{\sqrt{S_A}} - \frac{S_{Bj}}{\sqrt {S_B}} \right )^2 }$
• where $S_{T}$ is the total number of OTUs
• where $S_{Aj}$ is 1 if the abundance of the jth OTU in sample a is greater than zero, otherwise 0.
• where $S_{Bj}$ is 1 if the abundance of the jth OTU in sample b is greater than zero, otherwise 0.
• where $S_{a}$ is the number of nonzero OTUs in sample a.
• where $S_{b}$ is the number of nonzero OTUs in sample b.