13,345 research outputs found
Free fermionic propagators on a lattice
A method used recently to obtain a formalism for classical fields with
non-local actions preserving chiral symmetry and uniqueness of fermion fields
yields a discrete version of Huygens' principle with free discrete propagators
that recover their continuum forms in certain limit.Comment: LaTex document, 13 pages, 1 figure. Minor changes, two references
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The Dyer-Roeder relation in a universe with particle production
We have obtained analytical exact solutions of the Dyer-Roeder equation in a
cosmological model where creation of particles occurs at the expenses of the
gravitational field. We discussed the influences of inhomogeneities in the path
of a light beam on the apparent diameter of astrophysical objects and consider
both redshift independent as redshift dependent distributions of the
inhomogeneities.Comment: 7 pages, 4 figures. Accepted to be published in the Astronomy and
Astrophysics Journa
Confidence Statements for Ordering Quantiles
This work proposes Quor, a simple yet effective nonparametric method to
compare independent samples with respect to corresponding quantiles of their
populations. The method is solely based on the order statistics of the samples,
and independence is its only requirement. All computations are performed using
exact distributions with no need for any asymptotic considerations, and yet can
be run using a fast quadratic-time dynamic programming idea. Computational
performance is essential in high-dimensional domains, such as gene expression
data. We describe the approach and discuss on the most important assumptions,
building a parallel with assumptions and properties of widely used techniques
for the same problem. Experiments using real data from biomedical studies are
performed to empirically compare Quor and other methods in a classification
task over a selection of high-dimensional data sets
Tratamento e reciclagem de águas residuárias em sistema intensivo de produção de leite.
bitstream/item/65245/1/CT-75-Tratamento-e-reciclagem-de-aguas.pd
Cerca elétrica: alternativa viável e econômica para manejo de pastagens.
bitstream/item/65421/1/COT-48-Cerca-eletrica-alternativa.pd
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