275 research outputs found

    First-principles calculations of the self-trapped exciton in crystalline NaCl

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    The atomic and electronic structure of the lowest triplet state of the off-center (C2v symmetry) self-trapped exciton (STE) in crystalline NaCl is calculated using the local-spin-density (LSDA) approximation. In addition, the Franck-Condon broadening of the luminescence peak and the a1g -> b3u absorption peak are calculated and compared to experiment. LSDA accurately predicts transition energies if the initial and final states are both localized or delocalized, but 1 eV discrepancies with experiment occur if one state is localized and the other is delocalized.Comment: 4 pages with 4 embeddded figure

    Species and habitats in danger : estimating the relative risk posed by oil spills in the northern Baltic Sea

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    Large-scale oil spills can have adverse effects on biodiversity in coastal areas where maritime oil transportation is intense. In this article we conducted a spatial risk assessment to study the risk that potential tanker accidents pose to threatened habitat types and species living in the northern Baltic Sea, which has witnessed a rapid increase in maritime oil transportation within the past two decades. We applied a probabilistic method, which combines three components: a Bayesian network describing tanker accidents and uncertainties related to them, probabilistic maps showing the movement of oil, and a database of threatened species and habitats in the area. The results suggest that spatial risk posed by oil spills varies across the area, and does not correspond, for example, to the frequency of accidents in a given area. The relative risk is highest for seashore meadows, which is important to take into account when managing these habitats. Our analysis underlines the importance of a thorough risk assessment, which is not only based solely on one or two specific factors such as accident probabilities or the trajectories of spilled oil but also contains as broad a view of the consequences as possible. We believe that the probabilistic methodology applied in the study will be of high interest to people who have to cope with uncertainties typical for environmental risk assessment and management.Peer reviewe

    Putative risk alleles for LATE-NC with hippocampal sclerosis in population-representative autopsy cohorts

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    Limbic-predominant age-related TAR-DNA-binding protein-43 (TDP-43) encephalopathy with hippocampal sclerosis pathology (LATE-NC + HS) is a neurodegenerative disorder characterized by severe hippocampal CA1 neuron loss and TDP-43-pathology, leading to cognitive dysfunction and dementia. Polymorphisms in GRN, TMEM106B and ABCC9 are proposed as LATE-NC + HS risk factors in brain bank collections. To replicate these results in independent population-representative cohorts, hippocampal sections from brains donated to three such studies (Cambridge City over 75-Cohort [CC75C], Cognitive Function and Ageing Study [CFAS], and Vantaa 85+ Study) were stained with hematoxylin-eosin (n = 744) and anti-pTDP-43 (n = 713), and evaluated for LATE-NC + HS and TDP-43 pathology. Single nucleotide polymorphism genotypes in GRN rs5848, TMEM106B rs1990622 and ABCC9 rs704178 were determined. LATE-NC + HS (n = 58) was significantly associated with the GRN rs5848 genotype (chi(2)(2) = 20.61, P <0.001) and T-allele (chi(2)(1) = 21.04, P <0.001), and TMEM106B rs1990622 genotype (Fisher's exact test, P <0.001) and A-allele (chi(2)(1) = 25.75, P <0.001). No differences in ABCC9 rs704178 genotype or allele frequency were found between LATE-NC + HS and non-LATE-NC + HS neuropathology cases. Dentate gyrus TDP-43 pathology associated with GRN and TMEM106B variations, but the association with TMEM106B nullified when LATE-NC + HS cases were excluded. Our results indicate that GRN and TMEM106B are associated with severe loss of CA1 neurons in the aging brain, while ABCC9 was not confirmed as a genetic risk factor for LATE-NC + HS. The association between TMEM106B and LATE-NC + HS may be independent of dentate TDP-43 pathology.Peer reviewe

    Power, Connected Coalitions, and Efficiency: Challenges to the Council of the European Union

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    This article is concerned with challenges to reforming the voting procedures of the Council of the European Union (EU). The next major waves of EU enlargement will cause the Union to increase to a membership of first twenty-one, and then twenty-six or possibly even more states. How does enlargement affect the Council's inherent "capacity to act" under the currently used qualified majority voting rule? It is demon strated here that the expected increase in EU membership will most likely induce a larger "status quo bias" as compared to the present situation in the Council if the crucial majority decision quota is not lowered. In addition, the article is responding to some criticism that has been applied against assessing the leverage of EU governments in one of the EU's most important institutions: the Council of the EU. By resorting to techniques that capture the influence of a priori coalitions on the one hand and "connected coalitions" among EU governments on the other—applying n- person cooperative game theory—the piece illustrates how the assessment of relative voting leverage in the framework of weighted voting systems may be extended and applied to situations in which the specific distribu tion of members' preferences is known. These calculations are again relevant in the face of the upcoming rounds of EU enlargement and projects for institutional reform.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68064/2/10.1177_019251219902000404.pd

    A comparative analysis reveals weak relationships between ecological factors and beta diversity of stream insect metacommunities at two spatial levels

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    v. 5, p. 1235-1248, mar., 2015The hypotheses that beta diversity should increase with decreasing latitude and increase with spatial extent of a region have rarely been tested based on a comparative analysis of multiple datasets, and no such study has focused on stream insects. We first assessed how well variability in beta diversity of stream insect metacommunities is predicted by insect group, latitude, spatial extent, altitudinal range, and dataset properties across multiple drainage basins throughout the world. Second, we assessed the relative roles of environmental and spatial factors in driving variation in assemblage composition within each drainage basin. Our analyses were based on a dataset of 95 stream insect metacommunities from 31 drainage basins distributed around the world. We used dissimilaritybased indices to quantify beta diversity for each metacommunity and, subsequently, regressed beta diversity on insect group, latitude, spatial extent, altitudinal range, and dataset properties (e.g., number of sites and percentage of presences). Within each metacommunity, we used a combination of spatial eigenfunction analyses and partial redundancy analysis to partition variation in assemblage structure into environmental, shared, spatial, and unexplained fractions. We found that dataset properties were more important predictors of beta diversity than ecological and geographical factors across multiple drainage basins. In the within-basin analyses, environmental and spatial variables were generally poor predictors of variation in assemblage composition. Our results revealed deviation from general biodiversity patterns because beta diversity did not show the expected decreasing trend with latitude. Our results also call for reconsideration of just how predictable stream assemblages are along ecological gradients, with implications for environmental assessment and conservation decisions. Our findings may also be applicable to other dynamic systems where predictability is low

    British press attitudes towards the EU's global presence:from the Russian-Georgian War to the 2009 Copenhagen Summit

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    This article surveys the way in which British print media have presented the European Union (EU)'s global presence in the international arena by analysing two case studies which reflect two very distinctive areas of EU foreign policy: global climate change policy and the policy towards Russia. It employs frame analysis, allowing for the identification of the way in which the discourse of the press was categorized around a series of central opinions and ideas. Frames underscore the connections made by journalists between different events, policies or phenomena and their possible interpretations. The analysis highlights that acting through the common framework of the EU rather than unilaterally was a strategy preferred by the British press. These findings are in stark contrast with the deep Euroscepticism which characterizes press attitudes towards most policy areas, and is often considered to be rooted in the British political culture, media system, public opinion or the longstanding tradition of viewing the European continent as the other

    Introduction: Connecting with the Electorate? Parliamentary Communication in EU Affairs

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    ational parliaments have often been described as latecomers to European integration, but there is little doubt that they have developed the institutional means to become more involved over the last few years – and especially since the Lisbon Treaty. Accordingly, the main focus of the literature has been on this institutional adaptation and thus on the relationship between the parliament and the government in European Union (EU) affairs. Other parliamentary functions, and in particular those that relate to their citizens such as the communication function, by contrast, have been largely neglected. Yet democracy depends on a viable public debate on policy choices and political alternatives to allow citizens to make informed political (electoral) choices and to exercise democratic control. This collection therefore investigates whether, and how, individual members of parliament, political parties, or legislatures as institutions ‘link’ with their electorates in EU politics. This introduction discusses why engaging with the public in EU affairs is – or at least should be – an important aspect of parliamentary work, introduces parliamentary means of communication and assesses parliamentary incentives and disincentives ‘to go public’ in EU politics. (author's abstract
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