2,960 research outputs found
The subordinated processes controlled by a family of subordinators and corresponding Fokker-Planck type equations
In this work, we consider subordinated processes controlled by a family of
subordinators which consist of a power function of time variable and a negative
power function of stable random variable. The effect of parameters in
the subordinators on the subordinated process is discussed. By suitable
variable substitutions and Laplace transform technique, the corresponding
fractional Fokker-Planck-type equations are derived. We also compute their mean
square displacements in a free force field. By choosing suitable ranges of
parameters, the resulting subordinated processes may be subdiffusive, normal
diffusive or superdiffusive.Comment: 11 pages, accepted by J. Stat. Mech.: Theor. Ex
Influence of unsymmetrical periodicity on extraordinary transmission through periodic arrays of subwavelength holes
Quadrate hole array is explored to study the influence of unsymmetrical
periodicity on extraordinary optical transmission through periodic arrays of
subwavelength holes. It is found that the transmission efficiency of light and
the ratio between transmission efficiencies of horizontal and vertical
polarized light can be continuously tuned by rotating the quadrate hole array.
We can calculate out the transmission spectra (including the heights and
locations of peaks) for any rotation angle with a simple theoretical
model.Comment: 6 pages, 5 figure
Interference of surface plasmon polaritions controlled by the phase of incident light
Interference patterns of surface plasmon polaritons(SPPs) are observed in the
extraordinary optical transmission through subwavelength holes in optically
thick metal plate. It is found that the phase of incident light can be
transferred to SPPs. We can control the destructive and constructive
interference of SPPs by modulating the relative phase between two incident
beams. Using a slightly displaced Mach-Zehnder interferometer, we also observe
a SPPs interference pattern composed of bright and dark stripes.Comment: 3pages,5figure
The effect of flower position on variation and covariation in floral traits in a wild hermaphrodite plant
<p>Abstract</p> <p>Background</p> <p>Floral traits within plants can vary with flower position or flowering time. Within an inflorescence, sexual allocation of early produced basal flowers is often female-biased while later produced distal flowers are male-biased. Such temporal adjustment of floral resource has been considered one of the potential advantages of modularity (regarding a flower as a module) in hermaphrodites. However, flowers are under constraints of independent evolution of a given trait. To understand flower diversification within inflorescences, here we examine variation and covariation in floral traits within racemes at the individual and the maternal family level respectively in an alpine herb <it>Aconitum gymnandrum </it>(Ranunculaceae).</p> <p>Results</p> <p>We found that floral traits varied significantly with flower position and among families, and position effects were family-specific. Most of the variance of floral traits was among individuals rather than among flowers within individuals or among families. Significant phenotypic correlations between traits were not affected by position, indicating trait integration under shared developmental regulation. In contrast, positive family-mean correlations in floral traits declined gradually from basal to distal flowers (nine significant correlations among floral traits in basal flowers and only three in distal flowers), showing position-specificity. Therefore, the pattern and magnitude of genetic correlations decreased with flower position.</p> <p>Conclusions</p> <p>This finding on covariation pattern in floral reproductive structures within racemes has not been revealed before, providing insights into temporal variation and position effects in floral traits within plants and the potential advantages of modularity in hermaphrodites.</p
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