3,179 research outputs found
The Economics of Books
The tensions between books and book markets as expressions of culture and books as products in profit-making businesses are analysed and insights from the theory of industrial organisation are given. Governments intervene in the market for books through laws concerning prices of books, grants for authors and publishers, a lower value-added tax, public libraries and education in order to stimulate the diversity of books on offer, increase the density of retail outlets and to promote reading. An overview of the different ways by which countries differ in terms of market structures and government policies is given. Particular attention is paid to retail price maintenance. Due to differences between European countries it is not a good idea to harmonise European book policies. Our analysis suggests that the book market seems quite able to invent solutions to specific problems of the book trade and that, apart from promoting reading, there is little need for government intervention.books, publishers, authors, diversity, monopolistic competition, retail price maintenance, subsidies, libraries, internet
Combinatievorming in de akkerbouw : organisatie en resultaten van samenwerkende akkerbouwbedrijven
Standing in a crowded room: Exploring the relation between interest group system density and access to policymakers
Exploring the proportionality of representation in interest group mobilization and political access: the case of the Netherlands
Surveys reveal that there are great differences among citizens in their membership of political associations. Such differences plausibly lead to a better representation of interests of privileged citizens compared to other citizens. We examine the demographic groups (in terms of education, gender and immigration background) that tend to be members of interest groups. We also investigate the relation between the membership profile of associations and the propensity of interest groups to be routinely approached by policymakers. The results of our elite survey of Dutch interest associations indicate that relatively well-educated citizens and men are better represented in interest groups. Patterns of underrepresentation are not further exacerbated by the outreach of policy-makers, except that interest associations with a relatively large female membership are less likely to be consulted
Restarting parallel Jacobi-Davidson with both standard and harmonic Ritz values
We study the Jacobi-Davidson method for the solution of large generalized eigenproblems as they arise in MagnetoHydroDynamics. We have combined Jacobi-Davidson (using standard Ritz values) with a shift and invert technique. We apply a complete LU decomposition in which reordering strategies based on a combination of block cyclic reduction and domain decomposition result in a well-parallelizable algorithm. Moreover, we describe a variant of Jacobi-Davidson in which harmonic Ritz values are used. In this variant the same parallel LU decomposition is used, but this time as a preconditioner to solve the `correction` equation. The size of the relatively small projected eigenproblems which have to be solved in the Jacobi-Davidson method is controlled by several parameters. The influence of these parameters on both the parallel performance and convergence behaviour will be studied. Numerical results of Jacobi-Davidson obtained with standard and harmonic Ritz values will be shown. Executions have been performed on a Cray T3E
A parallel Jacobi-Davidson method for solving generalized eigenvalue problems in linear magnetohydrodynamics
We study the solution of generalized eigenproblems generated by a model which is used for stability investigation of tokamak plasmas. The eigenvalue problems are of the form , in which the complex matrices and are block tridiagonal, and is Hermitian positive definite. The Jacobi-Davidson method appears to be an excellent method for parallel computation of a few selected eigenvalues, because the basic ingredients are matrix-vector products, vector updates and inner products. The method is based on solving projected eigenproblems of order typically less than 30. The computation of an approximate solution of a large system of linear equations is usually the most expensive step in the algorithm. By using a suitable preconditioner, only a moderate number of steps of an inner iteration is required in order to retain fast convergence for the JD process. Several preconditioning techniques are discussed. It is shown, that for our application, a proper preconditioner is a complete block LU decomposition, which can be used for the computation of several eigenpairs. Reordering strategies based on a combination of block cyclic reduction and domain decomposition result in a well-parallelizable preconditioning technique. Results obtained on 64 processing elements of both a Cray T3D and a T3E will be shown
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