46 research outputs found

    Patterns of democracy: Coalition governance and majoritarian modification in the United Kingdom, 2010–2015

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    The UK is often regarded as the archetype of Westminster democracy and as the empirical antithesis of the power-sharing coalitions of Western Europe. Yet, in recent years a different account has emerged that focuses on the subtler institutional dynamics which limit the executive. It is to this body of scholarship that this article responds, locating the recent chapter of coalition government within the wider context of the UK’s democratic evolution. To do so, the article draws Lijphart’s two-dimensional typology of democracies, developing a refined framework that enables systematic comparison over time. The article demonstrates that between over the course of the 2010-15 Parliament, the UK underwent another period of majoritarian modification, driven by factors including the long-term influence of the constitutional forces unleashed under Labour and the short-term impact of coalition management. The article makes several important contributions, salient in the UK and beyond. Theoretically, it offers a critical rejoinder to debates regarding the relationship between institutional design and democratic performance. Methodologically, it demonstrates that the tools of large-scale comparison can be effectively scaled-down to facilitate withincase analysis. Empirically, it provides a series of conclusions regarding the tenability of the UK’s extant democratic architecture under the weight of pressures to which it continues to be subject

    Influence of phosphorus on copper sensitivity of fluvial periphyton: the role of chemical, physiological and community-related factors

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    The influence of eutrophication of fluvial ecosystems (caused by increased phosphorus concentrations) on periphyton Cu sensitivity is explored from a multi-scale perspective, going from the field to the laboratory. The study design included three tiers: a field study including the characterization of land use and the ecological state of the corresponding river sections in the Fluvià River watershed, an experimental investigation performed with natural periphyton from the previously studied stream sites in indoor channels, and finally a culture study in the laboratory. Results showed that differences in copper sensitivity of natural periphyton communities followed the gradient of nutrient concentration found in the field. Results from the culture experiments demonstrated that both, P-conditions during growth and P-content in the media are important factors modulating the toxicological response of algae to Cu. The observations from this study indicate that the ecological effects of metal pollution in rivers might be obscured by eutrophication

    Crassulacean acid metabolism in the context of other carbon-concentrating mechanisms in freshwater plants: a review

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    Inorganic carbon can be in short-supply in freshwater relative to that needed by freshwater plants for photosynthesis because of a large external transport limitation coupled with frequent depleted concentrations of CO2 and elevated concentrations of O2. Freshwater plants have evolved a host of avoidance, exploitation and amelioration strategies to cope with the low and variable supply of inorganic carbon in water. Avoidance strategies rely on the spatial variation in CO2 concentrations within and among lakes. Exploitation strategies involve anatomical and morphological features that take advantage of sources of CO2 outside of the water column such as the atmosphere or sediment. Amelioration strategies involve carbon concentrating mechanisms (CCM) based on uptake of bicarbonate, which is widespread, C4-fixation which is infrequent and Crassulacean Acid Metabolism (CAM) which is of intermediate frequency. CAM enables aquatic plants to take up inorganic carbon in the night. Furthermore, daytime inorganic carbon uptake is generally not inhibited and therefore CAM is considered to be a carbon conserving mechanism. CAM in aquatic plants is a plastic mechanism regulated by environmental variables and is generally down-regulated when inorganic carbon does not limit photosynthesis. CAM is regulated in the long term (acclimation during growth), but is also affected by environmental conditions in the short term (response on a daily basis). In aquatic plants CAM appears to be an ecologically important mechanism for increasing inorganic carbon uptake, since the in situ contribution from CAM to the C-budget generally is high (18-55%)

    Tracing Groundwater Geochemistry Using δ\u3csup\u3e13\u3c/sup\u3eC on San Salvador Island (Southeastern Bahamas): Impliations for Carbonate Island Hydrogeology and Dissolution

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    Mixing dissolution is a widely accepted process of karstification on carbonate platforms, but regional differences in climate and geology indicate that a universal application of this model is insufficient to assess water– limestone interactions in more specific island settings. A two-phase study investigating δ13C, carbon concentration, and other geochemical parameters took place on San Salvador Island, The Bahamas, to better understand its hydrologic characteristics and identify local controls on dissolution. In the initial phase, Crescent Pond and adjacent Crescent Top Cave, both with conduit connections to one another and to open marine water, were monitored over 1.5 normal tidal cycles and found to have little geochemical variation. Contrasting geochemical compositions between these two sites and the ocean illustrates the complexity of subsurface hydrology, while lower pH and δ13CDIC values in the cave suggest the potential for bacterially mediated dissolution. The second phase included a more comprehensive geochemical survey of 12 of the island’s surface/ subsurface water bodies, and found that water geochemistry was governed primarily by connectivity to the ocean and secondarily by topographic and vegetative settings. Geochemical relationships illustrated by regression analyses showed that biologic activity exerted additional controls over water geochemistry, with photosynthesis removing biotically respired CO2 and elevating organic carbon in surface waters, while biotically respired CO2 accumulates and supports dissolution in the subsurface. These data underscore the importance of including the role of biotic processes with climate and geologic settings when identifying dissolution mechanisms and using them to estimate modern and historical dissolution processes

    Effects of one valence proton on seniority and angular momentum of neutrons in neutron-rich(51)( 122-)(131)Sb isotopes

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    Background: Levels fulfilling the seniority scheme and relevant isomers are commonly observed features in semimagic nuclei; for example, in Sn isotopes (Z=50). Seniority isomers in Sn, with dominantly pure neutron configurations, directly probe the underlying neutron-neutron (νν) interaction. Furthermore, an addition of a valence proton particle or hole, through neutron-proton (νπ) interaction, affects the neutron seniority as well as the angular momentum. Purpose: Benchmark the reproducibility of the experimental observables, like the excitation energies (EX) and the reduced electric-quadrupole transition probabilities [B(E2)], with the results obtained from shell-model interactions for neutron-rich Sn and Sb isotopes with N<82. Study the sensitivity of the aforementioned experimental observables to the model interaction components. Furthermore, explore from a microscopic point of view the structural similarity between the isomers in Sn and Sb, and thus the importance of the valence proton. Methods: The neutron-rich Sb122–131 isotopes were produced as fission fragments in the reaction Be9(U238, f) with 6.2 MeV/u beam energy. A unique setup, consisting of AGATA, VAMOS++, and EXOGAM detectors, was used which enabled the prompt-delayed γ-ray spectroscopy of fission fragments in the time range of 100 ns to 200μs. Results: New isomers and prompt and delayed transitions were established in the even-A Sb122–130 isotopes. In the odd-A Sb123–131 isotopes, new prompt and delayed γ-ray transitions were identified, in addition to the confirmation of the previously known isomers. The half-lives of the isomeric states and the B(E2) transition probabilities of the observed transitions depopulating these isomers were extracted. Conclusions: The experimental data was compared with the theoretical results obtained in the framework of large-scale shell-model (LSSM) calculations in a restricted model space. Modifications of several components of the shell-model interaction were introduced to obtain a consistent agreement with the excitation energies and the B(E2) transition probabilities in neutron-rich Sn and Sb isotopes. The isomeric configurations in Sn and Sb were found to be relatively pure. Furthermore, the calculations revealed that the presence of a single valence proton, mainly in the g7/2 orbital in Sb isotopes, leads to significant mixing (due to the νπ interaction) of (i) the neutron seniorities (υν) and (ii) the neutron angular momentum (Iν). The above features have a weak impact on the excitation energies, but have an important impact on the B(E2) transition probabilities. In addition, a constancy of the relative excitation energies irrespective of neutron seniority and neutron number in Sn and Sb was observed.The neutron-rich 122131^{122-131}Sb isotopes were produced as fission fragments in the reaction 9^{9}Be(238^{238}U,~f) with 6.2 MeV/u beam energy. An unique setup, consisting of AGATA, VAMOS++ and EXOGAM detectors, was used which enabled the prompt-delayed gamma-ray (γ\gamma) spectroscopy of fission fragments in the time range of 100 ns - 200 μ\mus. New isomers, prompt and delayed transitions were established in the even-A 122130^{122-130}Sb isotopes. In the odd-A 123131^{123-131}Sb isotopes, new prompt and delayed γ\gamma-ray transitions were identified, in addition to the confirmation of the previously known isomers. The half-lives of the isomeric states and the B(E2)B(E2) transition probabilities of the observed transitions depopulating these isomers were extracted. The experimental data was compared with the theoretical results obtained in the framework of Large-Scale Shell-Model (LSSM) calculations in a restricted model space. Modifications of several components of the shell model interaction were introduced to obtain a consistent agreement with the excitation energies and the B(E2)B(E2) transition probabilities in neutron-rich Sn and Sb isotopes. The isomeric configurations in Sn and Sb were found to be relatively pure. Further, the calculations revealed that the presence of a single valence proton, mainly in the g7/2g_{7/2} orbital in Sb isotopes, leads to significant mixing (due to the νπ\nu\pi interaction) of: (i) the neutron seniorities (υν\upsilon_{\nu}) and (ii) the neutron angular momentum (IνI_{\nu}). The above features have a weak impact on the excitation energies, but have an important impact on the B(E2)B(E2) transition probabilities. In addition, a constancy of the relative excitation energies irrespective of neutron seniority and neutron number in Sn and Sb was observed
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