1,847 research outputs found

    Stabilization of the coupled oxygen and phosphorus cycles by the evolution of bioturbation

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    This is the author accepted manuscript. The final version is available from Nature Research via the DOI in this record Animal burrowing and sediment-mixing (bioturbation) began during the run up to the Ediacaran/Cambrian boundary, initiating a transition between the stratified Precambrian and more well-mixed Phanerozoic sedimentary records, against the backdrop of a variable global oxygen reservoir probably smaller in size than present. Phosphorus is the long-term limiting nutrient for oxygen production via burial of organic carbon, and its retention (relative to carbon) within organic matter in marine sediments is enhanced by bioturbation. Here we explore the biogeochemical implications of a bioturbation-induced organic phosphorus sink in a simple model. We show that increased bioturbation robustly triggers a net decrease in the size of the global oxygen reservoir - the magnitude of which is contingent upon the prescribed difference in carbon to phosphorus ratios between bioturbated and laminated sediments. Bioturbation also reduces steady-state marine phosphate levels, but this effect is offset by the decline in iron-adsorbed phosphate burial that results from a decrease in oxygen concentrations. The introduction of oxygen-sensitive bioturbation to dynamical model runs is sufficient to trigger a negative feedback loop: the intensity of bioturbation is limited by the oxygen decrease it initially causes. The onset of this feedback is consistent with redox variations observed during the early Cambrian rise of bioturbation, leading us to suggest that bioturbation helped to regulate early oxygen and phosphorus cycles. © 2014 Macmillan Publishers Limited. All rights reserved.Natural Environment Research Council (NERC)Inge Lehmann ScholarshipVILLUM FoundationNational Basic Research Program of ChinaNational Natural Science Foundation of ChinaDeutsche Forschungsgemeinschaft (DFG

    Relationship between FEV1 change and patient-reported outcomes in randomised trials of inhaled bronchodilators for stable COPD: a systematic review.

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    BACKGROUND: Interactions between spirometry and patient-reported outcomes in COPD are not well understood. This systematic review and study-level analysis investigated the relationship between changes in FEV1 and changes in health status with bronchodilator therapy. METHODS: Six databases (to October 2009) were searched to identify studies with long-acting bronchodilator therapy reporting FEV1 and health status, dyspnoea or exacerbations. Mean and standard deviations of treatment effects were extracted for each arm of each study. Relationships between changes in trough FEV1 and outcomes were assessed using correlations and random-effects regression modelling. The primary outcome was St George's Respiratory Questionnaire (SGRQ) total score. RESULTS: Thirty-six studies (≥ 3 months) were included. Twenty-two studies (23,654 patients) with 49 treatment arms each contributing one data point provided SGRQ data. Change in trough FEV1 and change in SGRQ total score were negatively correlated (r = -0.46, p < 0.001); greater increases in FEV1 were associated with greater reductions (improvements) in SGRQ. The correlation strengthened with increasing study duration from 3 to 12 months. Regression modelling indicated that 100 mL increase in FEV1 (change at which patients are more likely to report improvement) was associated with a statistically significant reduction in SGRQ of 2.5 (95% CI 1.9, 3.1), while a clinically relevant SGRQ change (4.0) was associated with 160.6 (95% CI 129.0, 211.6) mL increase in FEV1. The association between change in FEV1 and other patient-reported outcomes was generally weak. CONCLUSIONS: Our analyses indicate, at a study level, that improvement in mean trough FEV1 is associated with proportional improvements in health status

    Legislative Participation in the EU: An analysis of questions, speeches, motions and declarations in the 7th European Parliament

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    Which legislative activities in the European Parliament are ‘pluralistic’ – i.e. undertaken by all Members of the European Parliament, irrespective of legislative and electoral status? What type of parliamentary activity – if any – is dominated by party leaderships or vote-seekers in the European Union? This study will advance our knowledge of legislative politics in the EU by determining whether its legislature conforms to expectations from the legislative behaviour literature. This study compares the participation patterns in the EP7 (2009–2014) parliamentary questions, speeches, motions and written declarations via multilevel negative binomial regression. It makes use of a dataset on activity levels and demographics of 842 individual Members of the European Parliament serving between 2009 and 2014. The findings highlight that highly procedurally constrained activities, such as speeches and oral questions, are dominated by frontbenchers and vote-seekers, while procedurally ‘freer’ activities – written questions in particular – are very representative of the population of Members of the European Parliament. The analysis finds that there are both ‘pluralistic’ and vote-seeking activities in the ‘second order’ EU legislature, and that participation patterns broadly conform to patterns found in other established representative democracies

    Satisfaction with democracy in Turkey: findings from a national survey

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    A variety of factors affect citizens' satisfaction with democracy. Based on Turkey's political and economic context, as well as the existing literature, this study investigates the effect of four factors on people's satisfaction with democracy in Turkey: citizens' conceptualizations of democracy, being a political winner, citizens' perceptions of electoral integrity, and ethnic identity. Regression analysis of a nationally representative survey reveals that political losers and those with negative perceptions of electoral integrity are less satisfied with democracy in Turkey, while people's conceptualizations of democracy and ethnic identity do not have an effect on satisfaction with democracy. We conclude that, in Turkey, political polarization and negative perceptions of electoral integrity trigger a decline in citizens' satisfaction with democracy, which requires the attention of policymakers
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