Update README.md

Author: weimin-liu

README.md

@@ -77,8 +77,12 @@ basis, components = nmf(ims, feature_table, rk)
 basis, components, G = nmf(ims, feature_table, rk, n_run=20)
 ````
 
+## Notes:
+
+- Setting a higher `beta` parameter in Nimfa.Snmf() results in a more sparse matrix, useful in identify key peaks in reconstructed mass spectra.
+
 ## Credits
 
 - [francisbrochu/msvlm](https://github.com/francisbrochu/msvlm) for the `Spectrum` Class
 
-- [mims-harvard/nimfa](https://github.com/mims-harvard/nimfa) for the NMF analysis
+- [mims-harvard/nimfa](https://github.com/mims-harvard/nimfa) for the NMF analysis