20,576 research outputs found
Interpolation and scattered data fitting on manifolds using projected Powell–Sabin splines
We present methods for either interpolating data or for fitting scattered data on a two-dimensional smooth manifold. The methods are based on a local bivariate Powell-Sabin interpolation scheme, and make use of a family of charts {(Uξ , ξ)}ξ∈ satisfying certain conditions of smooth dependence on ξ. If is a C2-manifold embedded into R3, then projections into tangent planes can be employed. The data fitting method is a two-stage method. We prove that the resulting function on the manifold is continuously differentiable, and establish error bounds for both methods for the case when the data are generated by a smooth function
Feeding with chicory roots reduces the amount of odorous compounds in colon and rectal contents of pigs
Sixteen pigs (eight entire males and eight females) were given individually two diets, control and control added 25% chopped chicory roots for 2 months before slaughter. Samples were taken from the contents in colon and rectum and subjected to GC-MS analysis for amount of odour impact compounds. The compounds 2-pentanone, ethylbutyrate,
propylpropionate, butyric acid, ethyl-2-methylbutyrate, p-cresol, indole and skatole showed a significant difference between the two treatments. The esters, which have relatively pleasant, often fruity odours, increased in the chicory treatment, whereas the malodorous compounds, p-cresol, indole and skatole decreased in the chicory treatment. The measured amounts of compounds were corrected for their odour thresholds as different compounds can have widely different odour thresholds. Principal components analysis was then used to analyse the raw and corrected data results. p-Cresol was the most malodorous compound and together with skatole and indole count as the most malodorous compounds in the colon and rectum cotents. However, butyric acid also had some minor influence. Feeding chicory roots decreased significantly the concentrations of these malodorous compounds, especially if the lowest odour threshold values are used as correction factors
Scattered data fitting on surfaces using projected Powell-Sabin splines
We present C1 methods for either interpolating data or for fitting scattered data associated with a smooth function on a two-dimensional smooth manifold Ω embedded into R3. The methods are based on a local bivariate Powell-Sabin interpolation scheme, and make use of local projections on the tangent planes. The data fitting method is a two-stage method. We illustrate the performance of the algorithms with some numerical examples, which, in particular, confirm the O(h3) order of convergence as the data becomes dens
Color Transparency Effects in Electron Deuteron Interactions at Intermediate Q^2
High momentum transfer electrodisintegration of polarized and unpolarized
deuterium targets, is studied. We show that the importance of final
state interactions-FSI, occuring when a knocked out nucleon interacts with the
other nucleon, depends strongly on the momentum of the spectator nucleon. In
particular, these FSI occur when the essential contributions to the scattering
amplitude arise from internucleon distances . But the absorption
of the high momentum may produce a point like configuration, which
evolves with time. In this case, the final state interactions probe the point
like configuration at the early stage of its evolution. The result is that
significant color transparency effects, which can either enhance or suppress
computed cross sections, are predicted to occur for .Comment: 37 pages LaTex, 12 uuencoded PostScript Figures as separate file, to
be published in Z.Phys.
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