11,629 research outputs found
Application of remote sensing to solution of ecological problems
The application of remote sensing techniques to solving ecological problems is discussed. The three phases of environmental ecological management are examined. The differences between discovery and exploitation of natural resources and their ecological management are described. The specific application of remote sensing to water management is developed
Stellar model atmospheres with magnetic line blanketing. III. The role of magnetic field inclination
Context. See abstract in the paper.
Aims. In the last paper of this series we study the effects of the magnetic
field, varying its strength and orientation, on the model atmosphere structure,
the energy distribution, photometric colors and the hydrogen Balmer line
profiles. We compare with the previous results for an isotropic case in order
to understand whether there is a clear relation between the value of the
magnetic field angle and model changes, and to study how important the
additional orientational information is. Also, we examine the probable
explanation of the visual flux depressions of the magnetic chemically peculiar
stars in the context of this work.
Methods. We calculated one more grid of the model atmospheres of magnetic A
and B stars for different effective temperatures (Teff=8000K, 11000K, 15000K),
magnetic field strengths (B=0, 5, 10, 40 kG) and various angles of the magnetic
field (Omega=0-90 degr) with respect to the atmosphere plane. We used the
LLmodels code which implements a direct method for line opacity calculation,
anomalous Zeeman splitting of spectral lines, and polarized radiation transfer.
Results. We have not found significant changes in model atmosphere structure,
photometric and spectroscopic observables or profiles of hydrogen Balmer lines
as we vary the magnetic field inclination angle Omega. The strength of the
magnetic field plays the main role in magnetic line blanketing. We show that
the magnetic field has a clear relation to the visual flux depressions of the
magnetic CP stars.
Conclusions. See abstract in the paper.Comment: 10 pages, 5 figure
Erasable holographic medium using cis-trans isomerization
Photochemical process has been developed for recording of erasable holograms by utilizing reversible transformation of two isomers of molecule upon exposure to light. Hologram system records, reads, and erases in response to changes in refractive index of mixture of isomers
Accurate computation of Galerkin double surface integrals in the 3-D boundary element method
Many boundary element integral equation kernels are based on the Green's
functions of the Laplace and Helmholtz equations in three dimensions. These
include, for example, the Laplace, Helmholtz, elasticity, Stokes, and Maxwell's
equations. Integral equation formulations lead to more compact, but dense
linear systems. These dense systems are often solved iteratively via Krylov
subspace methods, which may be accelerated via the fast multipole method. There
are advantages to Galerkin formulations for such integral equations, as they
treat problems associated with kernel singularity, and lead to symmetric and
better conditioned matrices. However, the Galerkin method requires each entry
in the system matrix to be created via the computation of a double surface
integral over one or more pairs of triangles. There are a number of
semi-analytical methods to treat these integrals, which all have some issues,
and are discussed in this paper. We present novel methods to compute all the
integrals that arise in Galerkin formulations involving kernels based on the
Laplace and Helmholtz Green's functions to any specified accuracy. Integrals
involving completely geometrically separated triangles are non-singular and are
computed using a technique based on spherical harmonics and multipole
expansions and translations, which results in the integration of polynomial
functions over the triangles. Integrals involving cases where the triangles
have common vertices, edges, or are coincident are treated via scaling and
symmetry arguments, combined with automatic recursive geometric decomposition
of the integrals. Example results are presented, and the developed software is
available as open source
Phonographic neighbors, not orthographic neighbors, determine word naming latencies
The orthographic neighborhood size (N) of a word—the number of words that can be formed from that word by replacing one letter with another in its place—has been found to have facilitatory effects in word naming. The orthographic neighborhood hypothesis attributes this facilitation to interactive effects. A phonographic neighborhood hypothesis, in contrast, attributes the effect to lexical print-sound conversion. According to the phonographic neighborhood hypothesis, phonographic neighbors (words differing in one letter and one phoneme, e.g., stove and stone) should facilitate naming, and other orthographic neighbors (e.g., stove and shove) should not. The predictions of these two hypotheses are tested. Unique facilitatory phonographic N effects were found in four sets of word naming mega-study data, along with an absence of facilitatory orthographic N effects. These results implicate print-sound conversion—based on consistent phonology—in neighborhood effects rather than word-letter feedback
Methods of testing and diagnosing model error : dual and single route cascaded models of reading aloud
Models of visual word recognition have been assessed by both factorial and regression approaches. Factorial approaches tend to provide a relatively weak test of models, and regression approaches give little indication of the sources of models’ mispredictions, especially when parameters are not optimal. A new alternative method, involving regression on model error, combines these two approaches with parameter optimization. The method is illustrated with respect to the dual route cascaded model of reading aloud. In contrast to previous investigations, this method provides clear evidence that there are parameter-independent problems with the model, and identifies two specific sources of misprediction made by model
Review of \u3ci\u3ePrice Discrimination under the Robinson-Patman Act\u3c/i\u3e by Frederick M. Rowe
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