The holmium laser, which operates in a wavelength of 2.1 microns, is highly absorbed by water and has a shallow penetration depth of approximately 0.4 mm. As a pulsed mode laser, the Holmium reduces deeper thermal effects and charring which are more prevalent in Continues Wave lasers (e.g. Thulium, KTP).
In statistical theory, covariance is a measure of how much two random variables change together. In other words, covariance is a measure of the strength of the correlation between two random variables. Also, it can be considered as a generalization of the concept of variance of two random variables.
known, which makes this solution generally impractical. When the form of heteroscedasticity is unknown, the heteroscedasticity consistent. covariance matrix, hereafter HCCM, provides a consistent estimator of the covariance. matrix of the slope coeï¬cients in the presence of heteroscedasticity.