Note on Paper 'Optical Diffraction Analysis for Estimating Foliage Angle Distribution in Grassland Canopies', by J. A. Smith and J. K. Berry.

1980 ◽  
Vol 28 (4) ◽  
pp. 495
Author(s):  
ARG Lang
Keyword(s):  
Angular Distribution ◽  
Diffraction Analysis ◽  
Probability Density ◽  
Inclination Angle ◽  
Leaf Length ◽  
Optical Diffraction ◽  
Angle Distribution

It is shown that a technique previously described for analysing foliage angular distribution in grassland canopies is not well based theoretically because it does not give exact measures of the probability density of longitudinal leaf length with respect to inclination angle.

Extension of the Optical Diffraction Analysis Technique for Estimating Forest Canopy Geometry.

1979 ◽  
Vol 27 (5) ◽  
pp. 575 ◽  
Author(s):  
DS Kimes ◽  
JA Smith ◽  
JK Berry
Keyword(s):  
Diffraction Analysis ◽  
Pinus Contorta ◽  
Forest Canopy ◽  
Optical Diffraction ◽  
Angle Distribution ◽  
Coordinate Transformations ◽  
Frequency Distributions ◽  
Analysis Technique ◽  
Inclination Angles

Optical diffraction analysis of in situ ground photographs has previously been used to estimate foliage angle distributions in grassland canopies. These canopies are typically characterized by a single component-leaves-and the foliage is highly linear in nature. In this paper, the diffraction technique is extended to a multicomponent forest canopy containing needles and branches. Additional convolution and coordinate transformations are used to estimate the branch and needle angle frequency distributions for top, middle, and base sections of two lodgepole pine (Pinus contorta) trees. The resulting distributions show that the branch inclination angles tend to increase as one proceeds to the tree tops. The needle inclination angle distribution was relatively constant for all layers, and it is believed that this distribution is characteristic of a large class of needle-bearing species.

Light Optical Diffraction Studies of Macromolecular Ultrastructure

1970 ◽  
Vol 28 ◽  
pp. 258-259
Author(s):  
Glen B. Haydon
Keyword(s):  
High Resolution ◽  
Diffraction Analysis ◽  
Diffraction Pattern ◽  
Electron Micrographs ◽  
Optical Diffraction ◽  
Electron Micrograph ◽  
Its Analysis ◽  
Resolution Electron ◽  
Diffraction Patterns

Analysis of light optical diffraction patterns produced by electron micrographs can easily lead to much nonsense. Such diffraction patterns are referred to as optical transforms and are compared with transforms produced by a variety of mathematical manipulations. In the use of light optical diffraction patterns to study periodicities in macromolecular ultrastructures, a number of potential pitfalls have been rediscovered. The limitations apply to the formation of the electron micrograph as well as its analysis.(1) The high resolution electron micrograph is itself a complex diffraction pattern resulting from the specimen, its stain, and its supporting substrate. Cowley and Moodie (Proc. Phys. Soc. B, LXX 497, 1957) demonstrated changing image patterns with changes in focus. Similar defocus images have been subjected to further light optical diffraction analysis.

Optical Diffraction Analysis of Petrographic Thin Sections

Science ◽  
1974 ◽  
Vol 186 (4160) ◽  
pp. 234-239 ◽  
Author(s):  
P. C. Power ◽  
H. J. PincuS
Keyword(s):  
Diffraction Analysis ◽  
Optical Diffraction ◽  
Thin Sections

scholarly journals Bayesian hierarchical inference of asteroseismic inclination angles

2019 ◽  
Vol 488 (1) ◽  
pp. 572-589 ◽  
Author(s):  
James S Kuszlewicz ◽  
William J Chaplin ◽  
Thomas S H North ◽  
Will M Farr ◽  
Keaton J Bell ◽  
...  
Keyword(s):  
Inclination Angle ◽  
Angle Distribution ◽  
Data Set ◽  
Single Star ◽  
Bayesian Hierarchical ◽  
Hierarchical Method ◽  
Giant Stars ◽  
Inclination Angles ◽  
Red Giant Stars ◽  
Red Giant

Abstract The stellar inclination angle – the angle between the rotation axis of a star and our line of sight – provides valuable information in many different areas, from the characterization of the geometry of exoplanetary and eclipsing binary systems to the formation and evolution of those systems. We propose a method based on asteroseismology and a Bayesian hierarchical scheme for extracting the inclination angle of a single star. This hierarchical method therefore provides a means to both accurately and robustly extract inclination angles from red giant stars. We successfully apply this technique to an artificial data set with an underlying isotropic inclination angle distribution to verify the method. We also apply this technique to 123 red giant stars observed with Kepler. We also show the need for a selection function to account for possible population-level biases, which are not present in individual star-by-star cases, in order to extend the hierarchical method towards inferring underlying population inclination angle distributions.

The assembly of ribbon-shaped structures in low ionic strength extracts obtained from vertebrate smooth muscle

1973 ◽  
Vol 265 (867) ◽  
pp. 203-212 ◽  
Keyword(s):  
Smooth Muscle ◽  
Ionic Strength ◽  
Diffraction Analysis ◽  
Average Diameter ◽  
Smooth Muscle Myosin ◽  
Optical Diffraction ◽  
The Core ◽  
Regular Arrangement ◽  
Low Ionic Strength ◽  
Muscle Myosin

In actomyosin extracts from smooth muscle obtained at low ionic strength, an assembly of protein into long ribbon-shaped elements is observed to take place. These ribbons which range up to about 100 nm in width and up to many micrometres in length exhibit a strong repeat period of about 5.6 nm. Optical diffraction analysis shows that they possess a long repeat of 39.1 nm ± 0.4 nm. Tropomyosin purified from vertebrate smooth muscle can be induced to form the same ribbon-shaped elements. On removal of salt from solution the ribbons dissociate into fine filaments of average diameter about 8 nm which show subfilaments of about 2 to 3 nm diameter. In crude preparations the ribbons occur in solution together with myosin. If such preparations are left to stand for several days, ribbons may be found that show a visible 14 nm period which appears to arise from the presence of a regular arrangement of projections. Smooth muscle myosin alone assembles into cylindrical filaments which exhibit a regular arrangement of projections along their entire length, indicating an absence of polarity. These results indicate, as have those recently obtained from section material, that the myosin-containing component of vertebrate smooth muscle contains a protein that forms the core of the filament, which is responsible for its ribbon-like shape and which probably determines the polarity of the attached myosin molecules. It is proposed that this protein is tropomyosin.

VECTOR CORRELATIONS AND PRODUCT POLARIZATIONS IN THE N(2D) + D2 → ND + D REACTIVE SYSTEM

2012 ◽  
Vol 11 (05) ◽  
pp. 1005-1018 ◽  
Author(s):  
SHANSHAN NIE ◽  
TIANSHU CHU
Keyword(s):  
Angular Distribution ◽  
Cross Sections ◽  
Energy Surface ◽  
Center Of Mass ◽  
Classical Trajectory ◽  
Reactive System ◽  
Angle Distribution ◽  
Polar Form ◽  
Generalized Polarization ◽  
Vector Correlations

The vector correlations between products and reagents of the N (2D) + D 2 reaction are investigated by employing quasi-classical trajectory (QCT) calculation on the accurate DMBE potential energy surface (PES) of the 2A″ state. Stereo-dynamic quantities, including the four generalized polarization-dependent differential cross-sections (PDDCSs), the angular distribution P(θr), the dihedral-angle distribution P(φr), as well as the product rotational angular distribution in the polar form of P(θr, φr), are calculated in the center-of-mass (CM) frame. The results indicate that the product rotational angular momentum j′ not only aligns along the y-axis, but also orients to the negative direction of the y-axis. The isotope effect in the context of chemical stereo-dynamics and influences of different versions of ground-state PESs on vector correlations are shown and discussed.

Circular dichroism in the angular distribution of core photoelectrons from Si(001): A photoelectron-diffraction analysis

1995 ◽  
Vol 52 (20) ◽  
pp. 14927-14934 ◽  
Author(s):  
A. P. Kaduwela ◽  
H. Xiao ◽  
S. Thevuthasan ◽  
C. S. Fadley ◽  
M. A. Van Hove
Keyword(s):  
Angular Distribution ◽  
Circular Dichroism ◽  
Diffraction Analysis ◽  
Photoelectron Diffraction ◽  
Circular Dichroïsm
Sign in / Sign up

Export Citation Format

Share Document