97 research outputs found

    The Compensation mechanism in the rains model: the Norwegian targets for acidification.

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    The RAINS model is used to calculate cost minimising abatement policies subject to European-wide spatial restrictions on pollution. The principle for choosing environmental targets for the 1994 Oslo Protocol was closing a gap between benchmark- and critical loads for each grid with a uniform percentage. During the negotiations for the 1999 Gothenburg Protocol accumulated ecosystems exceedances was adapted as basis for gap closure, and overshooting of the constraints allowed as an option, provided compensation could be found within the same country. A theoretical discussion of this compensation mechanism is provided. A simulation study, using the full RAINS model, of the impact of different levels of targets for troublesome Norwegian grids is presented, and results in the form of changes in accumulated acidity excesses and costs for the participating countries are reported.Acid rain; RAINS; critical loads; gap closure; accumulated exceedances; compensation mechanism

    Methodology for forecasting in the Swedish–Norwegian market for el-certificates

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    In this paper we describe a novel methodology for forecasting in the Swedish-Norwegian el-certificate market, which is a variant of a tradable green certificate scheme. For the forecasting, the el-certificate market is integrated in the electricity-market model EMPS, which has weekly to hourly time-step length, whereas the planning horizon can be several years. Strategies for the certificate inventory are calculated by stochastic dynamic programming, whereas penalty-rates for non-compliance during the annual settlement of certificates are determined endogenously.In the paper the methodology is described, and we show the performance of the model under different cases that can occur in the el-certificate market. The general results correspond to theoretical findings in previous studies for tradable green certificate markets, in particular that price-scenarios spread out in such a way that the unconditional expected value of certificates is relatively stable throughout the planning period. In addition the presented methodologies allows to assess the actual dynamics of the certificate price due to climatic uncertainty. Finally, special cases are indentified where the certificate price becomes excessively high respectively zero, due the design-specific dynamics of the penalty rate. © 2015 Elsevier Ltd.Methodology for forecasting in the Swedish–Norwegian market for el-certificatesacceptedVersio

    Applying endogenous learning models in energy system optimization

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    Conventional energy production based on fossil fuels causes emissions which contribute to global warming. Accurate energy system models are required for a cost-optimal transition to a zero-emission energy system, an endeavor that requires an accurate modeling of cost reductions due to technological learning effects. In this review, we summarize common methodologies for modeling technological learning and associated cost reductions. The focus is on learning effects in hydrogen production technologies due to their importance in a low-carbon energy system, as well as the application of endogenous learning in energy system models. Finally, we present an overview of the learning rates of relevant low-carbon technologies required to model future energy systems.Comment: review paper: main article (11 pages), appendices (8 pages), references (4 pages

    Directional turnover towards larger-ranged plants over time and across habitats

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    Species turnover is ubiquitous. However, it remains unknown whether certain types of species are consistently gained or lost across different habitats. Here, we analysed the trajectories of 1827 plant species over time intervals of up to 78 years at 141 sites across mountain summits, forests, and lowland grasslands in Europe. We found, albeit with relatively small effect sizes, displacements of smaller- by larger-ranged species across habitats. Communities shifted in parallel towards more nutrient-demanding species, with species from nutrient-rich habitats having larger ranges. Because these species are typically strong competitors, declines of smaller-ranged species could reflect not only abiotic drivers of global change, but also biotic pressure from increased competition. The ubiquitous component of turnover based on species range size we found here may partially reconcile findings of no net loss in local diversity with global species loss, and link community-scale turnover to macroecological processes such as biotic homogenisation

    Safety of intravenous ferric carboxymaltose versus oral iron in patients with nondialysis-dependent CKD: an analysis of the 1-year FIND-CKD trial.

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    Background: The evidence base regarding the safety of intravenous (IV) iron therapy in patients with chronic kidney disease (CKD) is incomplete and largely based on small studies of relatively short duration. Methods: FIND-CKD (ClinicalTrials.gov number NCT00994318) was a 1-year, open-label, multicenter, prospective study of patients with nondialysis-dependent CKD, anemia and iron deficiency randomized (1:1:2) to IV ferric carboxymaltose (FCM), targeting higher (400-600 ”g/L) or lower (100-200 ”g/L) ferritin, or oral iron. A post hoc analysis of adverse event rates per 100 patient-years was performed to assess the safety of FCM versus oral iron over an extended period. Results: The safety population included 616 patients. The incidence of one or more adverse events was 91.0, 100.0 and 105.0 per 100 patient-years in the high ferritin FCM, low ferritin FCM and oral iron groups, respectively. The incidence of adverse events with a suspected relation to study drug was 15.9, 17.8 and 36.7 per 100 patient-years in the three groups; for serious adverse events, the incidence was 28.2, 27.9 and 24.3 per 100 patient-years. The incidence of cardiac disorders and infections was similar between groups. At least one ferritin level ≄800 ”g/L occurred in 26.6% of high ferritin FCM patients, with no associated increase in adverse events. No patient with ferritin ≄800 ”g/L discontinued the study drug due to adverse events. Estimated glomerular filtration rate remained the stable in all groups. Conclusions: These results further support the conclusion that correction of iron deficiency anemia with IV FCM is safe in patients with nondialysis-dependent CKD

    Prosodic structure and suprasegmental features:Short-vowel stĂžd in Danish

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    This paper presents a phonological analysis of a glottalization phenomenon in dialects of Danish known as ‘short-vowel stþd’. It is argued that both short-vowel stþd and common Danish stþd involve the attachment of a laryngeal feature to a prosodic node—specifically the mora. In the case of short-vowel stþd that mora lacks segmental content, as it is projected top-down due to local prosodic requirements, not bottom-up by segmental material. I show that this device provides an account of the distribution of short-vowel stþd as arising from the interplay of constraints on metrical structure (both lexically stored and computed by the grammar) and the requirement for morae to be featurally licensed. The analysis provides further evidence for the analysis of ‘tonal accents’ and related phenomena in terms of metrical structure rather than lexical tone or laryngeal features, and contributes to our understanding of the relationship between segmental and suprasegmental phonology in Germanic languages

    Cost-effective abatement of ground-level ozone in cities and for larger regions : implications of non-monotonicity

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    Ground-level ozone concentrations have adverse effects e.g. on human health and crops. Ozone is not emitted, but atmospheric reactions involving nitrogen oxides (NOx) and volatile organic compounds (VOCs) cause its formation. However, functions that relate precursor emissions to ozone concentrations are typically neither convex nor monotonic. Others have shown that corner solutions, where only one emission type is abated, can be cost-effective since the ozoneformation is non-convex. This paper shows that the non-monotonicity implies an even more radical abatement strategy in some cases: the optimal amount of NOx emitted can be larger than the amount emitted in no-control
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