In this work, a geometric invariant curve and surface normalization method is presented. Translation, scale and shear are normalized by Principal Component Analysis (PCA) whitening. Independent Component Analysis (ICA) and the third order moments are then employed for rotation and reflection normalization. By applying this normalization, curves and surfaces that are related by geometric transfo...

The action curve in Chara seems to depend (as in Nitella) on the outward movement of K(+) from the sap. Presumably the increase in permeability in the inner protoplasmic surface and the outward movement of K(+) destroy the concentration gradient of K(+) across the inner protoplasmic surface. Hence the outwardly directed P.D. disappears, causing the rise (spike) of the action curve. The outer pr...