Paul Smeyers

Educational research : why "what works" doesn't work

Introduction: P. Smeyers and M. DePaepe. 1. The Good Practices of Jozef Emiel Verheyden-Schoolman and Professor of Education at the Ghent University: M. Depaepe, F. Simon & A. van Gorp.2. Ovide Decroly, a Hero of Education: A. van Gorp. 3. Why Generalizability is not Generalicable: L. Fendler. 4. New Languages and Old Institutions: the Problems of Implementing New School Governance: Daniel Trohler. 5. Problematisation or Methodology: J.D. Marshall. 6. The Relevance of Irrelevant Research the Irrelevance of Relevant Research: P. Smeyers. 7. Expectations of What Scientific Research Could (Not) Do: Kathleen Coessens and Jean Paul van Bendegem. 8. Kuhnian Science and Education Research: Analytics of Practice and Training: Lynda Stone. 9. The International and the Excellend in Educational Research: David Bridges. 10. Technical Difficulties: the Workings of Practical Judgement: R. Smith. 11. The Science of Education - Disciplinary Knowledge on Non-Knowledge/Ignorance?: Edwin Keiner. Index. Notes on Contributors.

On the apsidal motion in close binaries due to the tidal deformations of the components

The paper is devoted to a confrontation of the apsidal-motion rates in close binaries due to the tidal perturbations of the stellar components that are predicted by Sternes formula (1939) with the corresponding apsidal-motion rates that are determined in the framework of the theory of the dynamic tides. Sternes formula is derived in the supposition that the orbital period and the stars rotational period are suciently long so that, in accordance with an earlier suggestion of Cowling (1938), the star is almost adjusted to the gravitational eld of the companion. From the point of view of the theory of the dynamic tides, the second-degree tide is then approximated at each instant by an appropriate linear combination of three second-degree tides which are considered to be static. In this limiting case, the rate of secular apsidal motion predicted by Sternes formula agrees, up to large orbital eccentricities, with the rate of secular apsidal motion determined in the framework of the theory of the dynamic tides and depends on the stars central mass condensation. For close binaries with shorter orbital periods, the use of Sternes formula leads to deviations because of the increasing influence of the compressibility of the stellar fluid and resonances of dynamic tides with lower-order g + -modes. The relative deviations may to amount to a few tens of percents for models of zero-age main sequence stars of 5M ,1 0M ,a nd 20M.

Rotational modes in a slowly and uniformly rotating star

A perturbation method is derived forr-modes in a slowly and uniformly rotating star. In contrast to previous studies, the perturbation of the gravitational potential is included in the perturbation method.On the assumption that the effects of the centrifugal force are taken into account in the equilibrium model up to the second order in the angular velocity, an eigenvalue problem of sixth-order in the radial coordinate is derived that allows one to determine the zeroth-order toroidal displacement field and the third-order term in the expansion of the eigenfrequency. Furthermore, another eigenvalue problem is derived that governs the first-order toroidal displacement field and the fourth-order term in the expansion of the eigenfrequency. This second eigenvalue problem is also of the sixth-order in the radial coordinate.It is shown that the third-order term in the expansion of the eigenfrequency is real, and that the fourth-order term is zero.

Nonadiabatic resonant dynamic tides and orbital evolution in close binaries

This investigation is devoted to the eects of nonadiabatic resonant dynamic tides generated in a uniformly rotating stellar component of a close binary. The companion is considered to move in a fixed Keplerian orbit, and the eects of the centrifugal force and the Coriolis force are neglected. Semi-analytical solutions for the linear, nonadiabatic resonant dynamic tides are derived by means of a two-time variable expansion procedure. The solution at the lowest order of approximation consists of the resonantly excited oscillation mode and displays a phase shift with respect to the tide-generating potential. Expressions are established for the secular variations of the semi-major axis, the orbital eccentricity, and the stars angular velocity of rotation caused by the phase shift. The orders of magnitude of these secular variations are considerably larger than those derived earlier by Zahn (1977) for the limiting case of dynamic tides with small frequencies. For a 5 M ZAMS star, an orbital eccentricity e= 0:5, and orbital periods in the range from 2 to 5 days, numerous resonances of dynamic tides with second-degree lower-order g + -modes are seen to induce secular variations of the semi-major axis, the orbital eccentricity, and

Stellar oscillations and magnetic field perturbations of the boundary conditions

The effect of a weak magnetic field on the adiabatic radial and non-radial oscillations of a stellar configuration is studied by means of a perturbation method. Special attention is devoted to the perturbation of the oscillation frequencies resulting from the change of the boundary conditions caused by the magnetic field. This change is related to the fact that the introduction of a magnetic field removes the singularity at the surface of the equilibrium configuration. The perturbation method is applied to Ferraros model and the influence of a magnetic field on the frequencies of the different types of oscillation modes is discussed.

Gravity modes in composite polytropic stars

We study gravity modes of composite polytropic stars which consist of two convectively stable zones separated by a convectively unstable zone. In addition to the unstable gravity modes associated with the intermediate zone, we distinguish two types of stable gravity modes, one type being mainly associated with the core, the other one being mainly associated with the envelope. We find also some accidental ‘resonances’ between the core and the envelope.

Tidal perturbations of linear, isentropic oscillations in components of circular-orbit close binaries II. Validity of the perturbation method applied to equilibrium tides

The paper is devoted to a verification of the validity of a first-order perturbation method that was developed in an earlier paper and allows one to determine the effects of an equilibrium tide on linear, isentropic oscillations of a component in a close binary. The verification is done by a comparison between results obtained by the perturbation method and results obtained in other ways, in the cases of two simple models: the compressible equilibrium sphere with uniform mass density and the polytropic model with index n = 3. In the first case, a comparison is made with second-harmonic oscillations in compressible Jeans spheroids with a small eccentricity, and in the second case, with results determined by Saio (1981) for a rotationally and tidally distorted polytrope. For the comparison, the second-harmonic oscillations of the incompressible and the compressible Jeans spheroids are redetermined by means of a method of direct integration of the governing equations which has the advantage of yielding exact analytical solutions of the eigenfrequency equations.

European Social Science Citation Index: A Chance for Promoting European Research?

In the context of increasingly common and frequent evaluations in Educational Science, the assurance of the quality of publications belongs to those challenges, which have not yet been solved adequately. In the face of new technical possibilities and the sheer volume of publications, it is important to find a new balance between a specialist public communication of the results and points of view of Educational Science and internal communication within the discipline, which promotes the development of the discipline as a whole. This contribution presents a discussion on how processes of quality assurance for publications within the European Research Area can be initiated which provide a better international visibility of research both carried out and published in Educational Science in Europe.

Asymptotic representation of low- and intermediate-degree p-modes in stars

A first-order asymptotic representation is developed for low- and intermediate-degree p-modes in stars for which the lower boundary of the resonant acoustic cavity is not located close to the stars centre. To this end, afourth-order system of differential equations in the radial parts of the divergence and the radial component of the Lagrangian displacement is adopted. The lower boundary of the resonant acoustic cavity is considered to be a turning point for one of the differential equations. As in a previous asymptotic study of low-degree p-modes with high radial orders, asymptotic expansion procedures applying to self-adjoint second-order differential equations with a large parameter are used by extension of these methods. The main result is that, in contrast with the usual first-order asymptotic theory for low-degree p-modes of high radial orders, the present first-order asymptotic representation leads to small frequency separations D n , f different from zero. The validity of the asymptotic representation is tested for p-modes of the equilibrium sphere with uniform mass density, since the modes of this model are determined by means of exact analytical solutions.

Child Rearing: Passivity and being able to go on. Wittgenstein on shared practices and seeing aspects

It is not uncommon to hear parents say in discussions they have with their children ‘Look at it this way’. And called upon for their advice, counsellors too say something to adults with the significance of ‘Try to see it like this’. The change of someones perspective in the context of child rearing is the focus of this paper. Our interest in this lies not so much in giving an answer to the practical problems that are at stake, but at disentangling the issues on a conceptual level. Within the so‐called second part of his Philosophical Investigations, Wittgenstein deals with shared practices and with concepts such as ‘seeing’ and ‘seeing as’. What he says there is in terms of content linked with his earlier Tractatus position concerning ethics, a matter which will first be dealt with. After that, the relevant sections of his later work are discussed. Following Cavell, it is concluded that to try to get someone to see what one sees, necessarily presupposes giving it out of ones hands. The passivity this points at highlights what Erziehung in the end comes down to.