Observation of Ising-like critical fluctuations in frustrated Josephson junction arrays with modulated coupling energies

We report the results of ac sheet conductance measurements performed on fully frustrated square arrays of Josephson junctions whose coupling energy is periodically modulated in one of the principal lattice directions. Such systems are predicted to exhibit two distinct transitions: a low-temperature Ising-like transition triggered by the proliferation of domain walls and a high-temperature transition driven by the vortex unbinding mechanism of the Beresinskii-Kosterlitz-Thouless (BKT) theory. Both the superfluid and dissipative components of the conductance are found to exhibit features which unambiguously demonstrate the existence of a double transition whose properties are consistent with the Ising-BKT scenario.Comment: To be published in Physica C (Proceedings of the 2nd European Conference in School Format 'Vortex Matter in Superconductors'

Political Conflict and Direct Democracy -- Explaining Initiative Use 1920-2011

Political competition is the engine for representative democracy. Within the representation mechanics I look at the political space, the dimensionality of political conflict, and how parties try to affect the relative salience of different dimensions by using direct democratic institutions. The leading question is how we can explain initiative use. The paper asks how the costs and benefits of using initiatives affect parties when they decide whether to use this instrument or not. The major argument is that when party competition increases, we will see higher initiative frequencies because parties try to affect the saliency of specific issues to increase their electoral bases. I analyze annual submission rates, the content of proposed initiatives, and the changing share of partisan actors behind initiatives. The findings highlight that the consequences of direct democratic institutions go beyond changing policy outcomes. For the specific case at hand, Switzerland from 1920 to 2011, it is shown that despite numerous opposite claims, there has been no underlying change in strategy or equilibrium but just a slow evolution of underlying factors such as institutional requirements and partisan competition

Is direct democracy effective? Yes, if it is citizens who start the process

The EU referendum this week has sparked extensive debates about the pros and cons of direct democracy. But Lucas Leemann writes that landmark votes like this may be the most atypical – and arguably worst – examples of direct democracy. He indicates that in cases where citizens have the ability to launch initiatives and call for referendums, it can play an important role in resolving problems on non-redistributive issues

Pulsed Multipole Injection for the MAX IV Storage Rings

The MAX IV facility presently under construction will include two storage rings for the production of synchrotron radiation. The 3 GeV ring will house insertion devices for the production of x-rays while the 1.5 GeV ring will serve UV and IR users. Both rings will be operated at a constant 500 mA of stored current with top-up shots supplied by the 3.5 GeV MAX IV linac acting as a full-energy injector. So far, injection into both storage rings has been designed us- ing a conventional approach: a closed four-kicker injection bump brings the stored beam to the septum blade where the injected bunches are captured in a single turn. Recently, studies have been carried out to investigate the feasibility of using a pulsed multipole for injection into the storage rings. Pulsed multipole injection does not require an injec- tion bump and has the potential to make top-up injection transparent to users. This paper reports on these studies and summarizes requirements for the pulsed sextupole magnet to be installed for injection into the MAX IV storage rings

Recent Progress on the MAX IV 1.5 GeV Storage Ring Lattice and Optics

Construction of the MAX IV facility started in 2010 and commissioning is expected to begin in 2014. Once com- pleted, the facility will include two storage rings for the production of synchrotron radiation. The 3 GeV ring will house insertion devices for the production of x-rays, while the 1.5 GeV ring will serve UV and IR users. Recently, the lattice and optics of the 1.5 GeV storage ring have been modified as a result of detailed magnet and vacuum system design. This paper discusses the lattice and optics changes as well as their effects

Gender inequalities in transnational academic mobility and the ideal type of academic entrepreneur

Based on a study on academic career paths of PhD graduates in Switzerland, this paper is concerned with the individual and institutional factors that affect transnational academic mobility in the postdoctoral period. It will be argued that the institutionalisation of geographic mobility in academic career paths through research funding institutions and universities have gendering and stratifying effects. Complex formations related to gender, partnership, children, and dual-career constellations, as well as to social class and academic integration, are resulting in inequalities in the accumulation of international cultural and social capital

Shrinkage and restrained shrinkage cracking of self-compacting concrete compared to conventionally vibrated concrete

Self-compacting concrete (SCC) used in Switzerland contains about 80l/m3 more volume of paste than conventionally vibrated concrete (CVC). Consequently, there are some systematic differences in the properties of the hardened concrete. Normally, shrinkage of SCC is higher than shrinkage of CVC. Therefore, risk of cracking in case of restrained deformations can be increased for SCC. In this study shrinkage of thirteen different SCC mixtures using volume of paste, water content, type of binder, grain size distribution or content of shrinkage reducing admixture (SRA) as variables was compared with shrinkage of three different CVC mixtures with constant volume of paste but variable w/b. Furthermore, the risk of cracking of the different SCC- and CVC-mixtures in restrained conditions was studied under constant and varying curing conditions. The results show that shrinkage is mainly depending on volume of paste. Due to the higher volume of paste, SCC displayed higher shrinkage than CVC. Adding an SRA was the only measure to reduce shrinkage of SCC to values of CVC. Restrained shrinkage cracking is depending on shrinkage rate, mechanical properties and drying velocity. For slow shrinkage stress development, cracking risk of SCC can be lower compared to CVC despite the higher shrinkage rat