Measuring Maximum Latewood Density By Image Analysis At The Cellular Level

A study was conducted to compare the precision of X-ray densitometry (XRD) and video image analysis (VIA) in measuring wood density of the last-formed latewood. The precision was determined by examining the convergence of the replicated measurements of maximum latewood density (MAXD). by XRD, and maximum percentage of cell-wall area (MAX%), by VIA. VIA was a more precise method for determining density of the last-formed tracheids than XRD. The linear relationship between MAXD and MAX% was significant at P < 0.01. The results indicate that MAX% can be used as an alternative to X-ray measurements of MAXD

Entropic measure of directional emissions in microcavity lasers

We propose a noble notion of the directional emission in microcavity lasers. First, Shannon entropy of the far-field profiles in the polar coordinate can quantify the degree of unidirectionality of the emission, while previous notions about the unidirectionality can not efficiently measure in the robust range against a variation of the deformation parameter. Second, a divergence angle of the directional emission is defined phenomenologically in terms of full width at half maximum, and it is barely applicable to a complicated peak structure. However, Shannon entropy of semi-marginal probability of the far-field profiles in the cartesian coordinate can present equivalent results, and moreover it is applicable to even the cases with a complicated peak structure of the emission