844 research outputs found
Fermi surface and order parameter driven vortex lattice structure transitions in twin-free YBa2Cu3O7
We report on small-angle neutron scattering studies of the intrinsic vortex
lattice (VL) structure in detwinned YBa2Cu3O7 at 2 K, and in fields up to 10.8
T. Because of the suppressed pinning to twin-domain boundaries, a new distorted
hexagonal VL structure phase is stabilized at intermediate fields. It is
separated from a low-field hexagonal phase of different orientation and
distortion by a first-order transition at 2.0(2) T that is probably driven by
Fermi surface effects. We argue that another first-order transition at 6.7(2)
T, into a rhombic structure with a distortion of opposite sign, marks a
crossover from a regime where Fermi surface anisotropy is dominant, to one
where the VL structure and distortion is controlled by the order-parameter
anisotropy.Comment: 4 pages, 3 figures (2 color), minor change
The combinatorics of the Baer-Specker group
Denote the integers by Z and the positive integers by N.
The groups Z^k (k a natural number) are discrete, and the classification up
to isomorphism of their (topological) subgroups is trivial. But already for the
countably infinite power Z^N of Z, the situation is different. Here the product
topology is nontrivial, and the subgroups of Z^N make a rich source of examples
of non-isomorphic topological groups. Z^N is the Baer-Specker group.
We study subgroups of the Baer-Specker group which possess group theoretic
properties analogous to properties introduced by Menger (1924), Hurewicz
(1925), Rothberger (1938), and Scheepers (1996). The studied properties were
introduced independently by Ko\v{c}inac and Okunev. We obtain purely
combinatorial characterizations of these properties, and combine them with
other techniques to solve several questions of Babinkostova, Ko\v{c}inac, and
Scheepers.Comment: To appear in IJ
Coalition theories: empirical evidence for dutch municipalities
The paper analyzes coalition formation in Dutch municipalities. After discussing the main features of the institutional setting, several theories are discussed, which are classified as size oriented, policy oriented and actor oriented models. A test statistic is proposed to determine the predictive power of these models. The empirical analysis shows that strategic positions as well as some of the distinguished preferences are important in the setting of Dutch municipalities. Especially, the dominant minimum number principle yields highly significant results for coalition formations in the period 1978–1986
Sometimes You Cannot Have It All: Party Switching and Affiliation Motivations as Substitutes
Existing research on when legislators switch parties reports inconsistent results about motivations for switching (e.g., office, ideology, and votes). I treat the motivations for party switching as substitutes and argue that many of the inconsistencies that persist can be explained by modelling the interactive effects between these motivations. For example, scholars differ in terms of whether they find that electoral considerations are an important determinant of party switching. The conflicting findings on the independent effects of electoral considerations are explained here by demonstrating that these effects are conditional on the level of office benefits a legislators enjoys, as well as the ideological distance between the legislator and party. More generally, the empirical analysis provides strong support for the substitution effect hypothesis. Thus, modelling interactive effects increases our understanding of party switching
Discovery of a woman portrait behind La Violoniste by Kees van Dongen through hyperspectral imaging
Exploring leadership in multi-sectoral partnerships
This article explores some critical aspects of leadership in the context of multi-sectoral partnerships. It focuses on leadership in practice and asks the question, `How do managers experience and perceive leadership in such partnerships?' The study contributes to the debate on whether leadership in a multi-sectoral partnership context differs from that within a single organization. It is based on the accounts of practising managers working in complex partnerships. The article highlights a number of leadership challenges faced by those working in multi-sectoral partnerships. Partnership practitioners were clear that leadership in partnerships was more complex than in single organizations. However, it was more difficult for them to agree a consensus on the essential nature of leadership in partnership. We suggest that a first-, second- and third-person approach might be a way of better interpreting leadership in the context of partnerships
Magnetic-field-induced nonlocal effects on the vortex interactions in twin-free YBa2Cu3O7
The vortex lattice (VL) in the high-kappa superconductor YBa2Cu3O7, at 2 K
and with the magnetic field parallel to the crystal c-axis, undergoes a
sequence of transitions between different structures as a function of applied
magnetic field. However, from structural studies alone, it is not possible to
determine precisely the system anisotropy that governs the transitions between
different structures. To address this question, here we report new small-angle
neutron scattering measurements of both the VL structure at higher
temperatures, and the field- and temperature-dependence of the VL form factor.
Our measurements demonstrate how the influence of anisotropy on the VL, which
in theory can be parameterized as nonlocal corrections, becomes progressively
important with increasing magnetic field, and suppressed by increasing the
temperature towards Tc. The data indicate that nonlocality due to different
anisotropies play important roles in determining the VL properties.Comment: To appear in Phys. Rev.
A theoretical model to elucidate the elusive concept ‘voice' for interpreters
This paper is an attempt to elucidate the concept of voice for interpreters in relation to the equally elusive concept pleasant voice for interpreters. The point of departure is that the concept voice for interpreting has to do with the physical properties of a speaker’s voice, which may lead to the effect that a speaker’s voice is heard as pleasant or unpleasant by a listener, depending on how a speaker uses or deploys these physical properties. The paper employs an interdisciplinary approach to reviewing relevant literature and shows that for better interpreter education and interpreting assessment, there is a need to unravel, and unify existing understandings of the concept voice. A new definition is therefore proposed. The new definition consists of a cluster of suprasegmental features resulted from supralaryngeal and laryngeal activities and incorporates in what are traditionally known as fluency features in interpreting. The paper goes on to discuss the potential benefits and implications of the newly proposed definition for both interpreter training and interpreting studies
Worker remittances and the global preconditions of ‘smart development’
With the growing environmental crisis affecting our globe, ideas to weigh economic or social progress by the ‘energy input’ necessary to achieve it are increasingly gaining acceptance. This question is intriguing and is being dealt with by a growing number of studies, focusing on the environmental price of human progress. Even more intriguing, however, is the question of which factors of social organization contribute to a responsible use of the resources of our planet to achieve a given social result (‘smart development’). In this essay, we present the first systematic study on how migration – or rather, more concretely, received worker remittances per GDP – helps the nations of our globe to enjoy social and economic progress at a relatively small environmental price. We look at the effects of migration on the balance sheets of societal accounting, based on the ‘ecological price’ of the combined performance of democracy, economic growth, gender equality, human development, research and development, and social cohesion. Feminism in power, economic freedom, population density, the UNDP education index as well as the receipt of worker remittances all significantly contribute towards a ‘smart overall development’, while high military expenditures and a high world economic openness are a bottleneck for ‘smart overall development’
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