223 research outputs found
Frustrated H-Induced Instability of Mo(110)
Using helium atom scattering Hulpke and L"udecke recently observed a giant
phonon anomaly for the hydrogen covered W(110) and Mo(110) surfaces. An
explanation which is able to account for this and other experiments is still
lacking. Below we present density-functional theory calculations of the atomic
and electronic structure of the clean and hydrogen-covered Mo(110) surfaces.
For the full adsorbate monolayer the calculations provide evidence for a strong
Fermi surface nesting instability. This explains the observed anomalies and
resolves the apparent inconsistencies of different experiments.Comment: 4 pages, 2 figures, submitted to PR
Challenging assumptions of the enlargement literature : the impact of the EU on human and minority rights in Macedonia
This article argues that from the very start of the transition process in Macedonia, a fusion of concerns about security and democratisation locked local nationalist elites and international organisations intoa political dynamic that prioritised security over democratisation. This dynamic resulted in little progress in the implementation of human and minority rights until 2009, despite heavy EU involvement in Macedonia after the internal warfare of 2001. The effects of this informally institutionalised relationship have been overlooked by scholarship on EU enlargement towards Eastern Europe, which has made generalisations based on assumptions relevant to the democratisation of countries in Eastern Europe, but not the Western Balkans
Looking by grazing incidence small angle x-ray scattering at gold nanoparticles supported on rutile TiO2(110) during CO oxidation
Theory of adsorbate induced surface reconstruction on W(100)
We report results of a theoretical study on an adsorbate induced surface
reconstruction. Hydrogen adsorption on a W(100) surface causes a switching
transition in the symmetry of the displacements of the W atoms within the
ordered c(2x2) phase. This transition is modeled by an effective Hamiltonian,
where the hydrogen degrees of freedom are integrated out. Based on extensive
Monte Carlo renormalisation group calculations we show that the switching
transition is of second order at high temperatures and of first order at low
temperatures. This behavior is qualitatively explained in terms of an XY model
where there is an interplay between four and eight fold anisotropy fields. We
also compare the calculated phase diagrams with a simple mean field theory.Comment: CSC Preprint, 31 pages (plain TeX file, no figures
Global Governance Behind Closed Doors : The IMF Boardroom, the Enhanced Structural Adjustment Facility, and the Intersection of Material Power and Norm Change in Global Politics
Up on the 12th floor of its 19th Street Headquarters, the IMF Board sits in active session for an average of 7 hours per week. Although key matters of policy are decided on in the venue, the rules governing Boardroom interactions remain opaque, resting on an uneasy combination of consensual decision-making and weighted voting. Through a detailed analysis of IMF Board discussions surrounding the Enhanced Structural Adjustment Facility (ESAF), this article sheds light on the mechanics of power in this often overlooked venue of global economic governance. By exploring the key issues of default liability and loan conditionality, I demonstrate that whilst the Boardroom is a more active site of contestation than has hitherto been recognized, material power is a prime determinant of both Executive Directorsâ preferences and outcomes reached from discussions. And as the decisions reached form the backbone of the âinstruction sheetâ used by Fund staff to guide their everyday operational decisions, these outcomesâand the processes through which they were reachedâwere factors of primary importance in stabilizing the operational norms at the heart of a controversial phase in the contemporary history of IMF concessional lending
Structure and growth of titanium buffer layers on Al2O3(0001)
The structure of titanium films on \alpha - Al2O3(0001) surfaces at room
temperature was investigated through in situ reflection high energy electron
diffraction (RHEED). The \alpha-phase of titanium was observed to grow with the
Ti(0001) || Al2O3(0001), Ti[1100] || Al2O3[2110] and Ti[1010] || Al2O3[1100]
epitaxy. For up to 6 nm thick films, an other structure was found to coexist
with \alpha-Ti. Its presence has dramatic consequences for the wetting of
silver, which partly explains the nontrivial buffer effect of titanium at the
silver/alumina interface. From the RHEED data, the extra structure is assigned
to the high-pressure hexagonal \omega-Ti phase. This is supported by
tight-binding total energy calculations that demonstrate that the \omega phase
could actually be stabilized by the \alpha - Al2O3(0001) substrate
Learning in the European Union: Theoretical Lenses and Meta-Theory
notes: This paper is based on research carried out with the support of the European Research Council grant on Analysis of Learning in Regulatory Governance, ALREG http://centres.exeter.ac.uk/ceg/research/ALREG/index.php. The authors wish to express their gratitude to the other authors in this special edition and in particular its editor, Nikos Zaharaidis and X anonymous referees.publication-status: AcceptedThe European Union may well be a learning organization, yet there is still confusion about the nature of learning, its causal structure and the normative implications. In this article we select four perspectives that address complexity, governance, the agency-structure nexus, and how learning occurs or may be blocked by institutional features. They are transactional theory, purposeful opportunism, experimental governance, and the joint decision trap. We use the four cases to investigate how history and disciplinary traditions inform theory; the core causal arguments about learning; the normative implications of the analysis; the types of learning that are theoretically predicted; the meta-theoretical aspects and the lessons for better theories of the policy process and political scientists more generally
Regional actorness and interregional relations:ASEAN, the EU and Mercosur
The European Union (EU) has a long tradition of interregional dialogue mechanisms with other regional organisations and is using these relations to project its own model of institutionalised actorness. This is partly motivated by the emerging actorness of the EU itself, which benefits from fostering capable regional counterparts in other parts of the world. This article advances the argument that actorness, which we conceptualise in terms of institutions, recognition and identity, is a relational concept, dependent on context and perception. Taking the Association of Southeast Asian Nations (ASEAN) and the Common Market of the South (Mercosur) and their relations with the EU as case studies, this article demonstrates that the actorness capabilities of all three organisations have been enhanced as result of ASEAN-EU and Mercosur-EU relations. However, there are clear limits to the development of the three components of regional actorness and to the interregional relations themselves. These limits stem both from the type of interregionalism at play and from the different regional models the actors incorporate. While there is evidence of institutional enhancement in ASEAN and Mercosur, these formal changes have been grafted on top of firmly entrenched normative underpinnings. Within the regional organisations, interactions with the EU generate centrifugal forces concerning the model to pursue, thus limiting their institutional cohesion and capacity. In addition, group-to-group relations have reinforced ASEAN and Mercosur identities in contrast to the EU. The formation of such differences has narrowed the scope of EU interregionalism despite the initial success of improved regional actorness
Attenuating Mutations in nsP1 Reveal Tissue-Specific Mechanisms for Control of Ross River Virus Infection
Ross River virus (RRV) is one of a group of mosquito-transmitted alphaviruses that cause debilitating, and often chronic, musculoskeletal disease in humans. Previously, we reported that replacement of the nonstructural protein 1 (nsP1) gene of the mouse-virulent RRV strain T48 with that from the mouse-avirulent strain DC5692 generated a virus that was attenuated in a mouse model of disease. Here we find that the six nsP1 nonsynonymous nucleotide differences between strains T48 and DC5692 are determinants of RRV virulence, and we identify two nonsynonymous nucleotide changes as sufficient for the attenuated phenotype. RRV T48 carrying the six nonsynonymous DC5692 nucleotide differences (RRV-T48-nsP16M) was attenuated in both wild-type and Rag1â/â mice. Despite the attenuated phenotype, RRV T48 and RRV-T48-nsP16M loads in tissues of wild-type and Rag1â/â mice were indistinguishable from 1 to 3 days postinoculation. RRV-T48-nsP16M loads in skeletal muscle tissue, but not in other tissues, decreased dramatically by 5 days postinoculation in both wild-type and Rag1â/â mice, suggesting that the RRV-T48-nsP16M mutant is more sensitive to innate antiviral effectors than RRV T48 in a tissue-specific manner. In vitro, we found that the attenuating mutations in nsP1 conferred enhanced sensitivity to type I interferon. In agreement with these findings, RRV T48 and RRV-T48-nsP16M loads were similar in mice deficient in the type I interferon receptor. Our findings suggest that the type I IFN response controls RRV infection in a tissue-specific manner and that specific amino acid changes in nsP1 are determinants of RRV virulence by regulating the sensitivity of RRV to interferon
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