The Europeanisation of national political systems : Parliaments and executives

This article reviews the by now extensive literature on the Europeanisation of the political systems of the EU-15, with an emphasis on parliaments and executives (i.e., governments and ministerial administrations). The Living Review highlights apparently contradictory effects of integration: de-parlamentarisation vs. re-parlamentarisation; bureaucratisation vs. politicisation; and centralisation vs. diffusion. These diverging assessments of the effects of integration do, in part, reflect diversity in the EU-15; in part, they are, however, also a result of differences in the specification of variables, research designs and theoretical approaches. Work that inquires into patterns of Europeanisation – across institutional domains, countries, regions and time – and which seeks to tackle the ‘methodological nationalism’ of the Europeanisation literature promises a clearer picture of the institutional consequences of European integration than we possess at present

A novel vacuum ultra violet lamp for metastable rare gas experiments

We report on a new design of a vacuum ultra violet (VUV) lamp for direct optical excitation of high laying atomic states e.g. for excitation of metastable rare gas atoms. The lamp can be directly mounted to ultra high vacuum vessels (p <= 10^(-10) mbar). It is driven by a 2.45 GHz microwave source. For optimum operation it requires powers of approximately 20 W. The VUV light is transmitted through a magnesium fluoride window, which is known to have a decreasing transmittance for VUV photons with time. In our special setup, after a run-time of the VUV lamp of 550 h the detected signal continuously decreased to 25 % of its initial value. This corresponds to a lifetime increase of two orders of magnitude compared to previous setups or commercial lamps

Solidifying system of democracy in the Central and Eastern European new EU members

The paper examines the requirements of an effective and legitimized democratic political system in the process of transition. The analysis and the conclusions are based on the Hungarian experience, which can carefully be applied to all Central and Eastern European (CEE) countries. Special focus is given to the relationship of legal certainty and the efficiency of the democratic system, to the tension between legalism and managerialism and to the characteristics of civil society organizations. In the conclusion special features of the transitional countries are pointed out

Interplay between phase defects and spin polarization in the specific heat of the spin density wave compound (TMTTF)_2Br in a magnetic field

Equilibrium heat relaxation experiments provide evidence that the ground state of the commensurate spin density wave (SDW) compound (TMTTF)$_2$Br after the application of a sufficient magnetic field is different from the conventional ground state. The experiments are interpreted on the basis of the local model of strong pinning as the deconfinement of soliton-antisoliton pairs triggered by the Zeeman coupling to spin degrees of freedom, resulting in a magnetic field induced density wave glass for the spin carrying phase configuration.Comment: 4 pages, 5 figure

On the equivalence of strong formulations for capacitated multi-level lot sizing problems with setup times

Several mixed integer programming formulations have been proposed for modeling capacitated multi-level lot sizing problems with setup times. These formulations include the so-called facility location formulation, the shortest route formulation, and the inventory and lot sizing formulation with (l,S) inequalities. In this paper, we demonstrate the equivalence of these formulations when the integrality requirement is relaxed for any subset of binary setup decision variables. This equivalence has significant implications for decomposition-based methods since same optimal solution values are obtained no matter which formulation is used. In particular, we discuss the relax-and-fix method, a decomposition-based heuristic used for the efficient solution of hard lot sizing problems. Computational tests allow us to compare the effectiveness of different formulations using benchmark problems. The choice of formulation directly affects the required computational effort, and our results therefore provide guidelines on choosing an effective formulation during the development of heuristic-based solution procedures

Thermodynamic Properties of the Incommensurate Phase of CuGeO_3

We present high resolution measurements of the specific heat and the thermal expansion of the inorganic spin--Peierls cuprate CuGeO_3 in a magnetic field of 16 Tesla. At the transition from the incommensurate to the uniform phase both quantities show pronounced anomalies, which allow to derive the uniaxial pressure dependencies of the transition temperature. In high magnetic fields the specific heat is dominated by magnetic excitations and follows a T^3 law at low temperatures. The thermal expansion measurements show the occurrence of spontaneous strains along all three lattice constants and yield high resolution measurements of the temperature dependence of the incommensurate structural distortion. The sizes of the spontaneous strains in the incommensurate phase are significantly reduced, but both their anisotropy as well as their temperature dependencies are very similar to those in zero field.Comment: 12 pages (Latex), 4 Figs. (PS), to appear in Phys. Rev. B54 (Vol.21

Magnetic excitations and effects of magnetic fields on the spin-Peierls transition in CuGeO3_3

We analyze the magnetic excitations of a spin-1/2 antiferromagnetic Heisenberg model with alternating nearest neighbor interactions and uniform second neighbor interactions recently proposed to describe the spin-Peierls transition in CuGeO$_3$. We show that there is good agreement between the calculated excitation dispersion relation and the experimental one. We have also shown that this model reproduces satisfactorily the experimental results for the magnetization vs. magnetic field curve and its saturation value. The model proposed also reproduces qualitatively some features of the magnetic phase diagram of this compound and the overall behavior of the magnetic specific heat in the presence of applied magnetic fields.Comment: 12 pages Revtex v2.0 + 4 figures postscripts include

Phenomenological model of elastic distortions near the spin-Peierls transition in CuGeO3CuGeO_3

A phenomenological model of the Landau type forms the basis for a study of elastic distortions near the spin-Peierls transition $T_c$ in $CuGeO_3$. The atomic displacements proposed by Hirota {\it et al.} [Phys. Rev. Lett. {\bf 73}, 736 (1994)] are accounted for by the model which includes linear coupling between $Cu$ and $O$ distortions. $Cu$ displacements are seen to be responsible for anomalies in the elastic properties {\it at} $T_c$, whereas incipient $O$ distortions give rise to temperature dependence below $T_c$. A discussion of possible critical behavior is also made.Comment: 1 figure available upon reques

Study of the magnetic susceptibility in the spin-Peierls system CuGeO3_3

We study numerically, using a one-dimensional Heisenberg model, the spin-Peierls transition in the linear Cu$^{2+}$ spin-1/2 chains in the inorganic compound CuGeO$_3$ which has been recently observed experimentally. We suggest that the magnetic susceptibility, the temperature dependence of the spin gap and the spin-Peierls transition temperature of this material can be reasonably described by including nearest and next nearest neighbor antiferromagnetic interactions along the chain. We estimate that the nearest neighbor exchange parameter J is approximately $160\:\rm K$, and that the next nearest neighbor exchange parameter is approximately $0.36\:\rm J$.Comment: 14 pages, Revtex v2.0, 4 figures available upon reques