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.
Measurement model invariance: same factor loadings, same item intercepts, (possibly) same residual (co)variances Measurement model invariance is a precursor to ANY group comparison (whether it is tested/acknowledged or not) â¢ Measurement invariance is often assumed, not tested Even a tâtest assumes measurement invariance Modeling change over time assumes measurement invariance People tend to accept this assumption unless you try to use a factor modelâ¦ then they usually insist on testing invariance