Advantages and Limitations of Direct PCR Amplification of Bacterial 16S-rDNA from Resected Heart Tissue or Swabs Followed by Direct Sequencing for Diagnosing Infective Endocarditis: A Retrospective Analysis in the Routine Clinical Setting

Infective endocarditis (IE) is a life-threatening disease that is associated with high morbidity and mortality. Its long-term prognosis strongly depends on a timely and optimized antibiotic treatment. Therefore, identification of the causative pathogen is crucial and currently based on blood cultures followed by characterization and susceptibility testing of the isolate. However, antibiotic treatment starting prior to blood sampling or IE caused by fastidious or intracellular microorganisms may cause negative culture results. Here we investigate the additional diagnostic value of broad-range PCR in combination with direct sequencing on resected heart tissue or swabs in patients with tissue or swab culture-negative IE in a routine clinical setting. Sensitivity, specificity, and positive and negative predictive values of broad-range PCR from diagnostic material in our patients were 33.3%, 76.9%, 90.9%, and 14.3%, respectively. We identified a total of 20 patients (21.5%) with tissue or culture-negative IE who profited by the additional application of broad-range PCR. We conclude that broad-range PCR on resected heart tissue or swabs is an important complementary diagnostic approach. It should be seen as an indispensable new tool for both the therapeutic and diagnostic management of culture-negative IE and we thus propose its possible inclusion in Duke’s diagnostic classification scheme

Economic evaluation of maintenance strategies for wind turbines : a stochastic analysis

The authors develop a stochastic model for assessing the life-cycle cost and availability of wind turbinesresulting from different maintenance scenarios, with the objective to identify the most cost-effective maintenancestrategy. Using field-data-based reliability models, the wind turbine – in terms of reliability – is modelled as a serialconnection of the most critical components. Both direct cost for spare parts, labour and access to the turbine, as wellas indirect cost from production losses are explicitly taken into account. The model is applied to the case of a VestasV44–600 kW wind turbine. Results of a reliability-centred maintenance analysis of this wind turbine are used to selectthe most critical wind turbine components and to identify possible maintenance scenarios. This study reveals thatcorrective maintenance is the most cost-effective maintenance strategy for the gearbox and the generator of the V44turbine, while the cost benefit of condition-based maintenance using online condition-monitoring systems increaseswith higher electricity price, turbine capacity and remoteness of sites.QC 20150626</p

Sustainable energy futures: Methodological challenges in combining scenarios and participatory multi-criteria analysis

This paper analyses the combined use of scenario building and participatory multi-criteria analysis (PMCA) in the context of renewable energy from a methodological point of view. Scenarios have been applied increasingly in decision-making about long-term consequences by projecting different possible pathways into the future. Scenario analysis accounts for a higher degree of complexity inherent in systems than the study of individual projects or technologies. MCA is a widely used appraisal method, which assesses options on the basis of a multi-dimensional criteria framework and calculates rankings of options. In our study, five renewable energy scenarios for Austria for 2020 were appraised against 17 sustainability criteria. A similar process was undertaken on the local level, where four renewable energy scenarios were developed and evaluated against 15 criteria. On both levels, the scenario development consisted of two stages: first an exploratory stage with stakeholder engagement and second a modelling stage with forecasting-type scenarios. Thus, the scenarios consist of a narrative part (storyline) and a modeled quantitative part. The preferences of national and local energy stakeholders were included in the form of criteria weights derived from interviews and participatory group processes, respectively. Especially in the case of renewable energy promotion in Austria, the paper systematically analyses the potentials and limitations of the methodology (1) for capturing the complexity of decision-making about the long-term consequences of changes in socio-economic and biophysical systems and (2) for appraising energy futures. The paper concludes that assessing scenarios with PMCA is resource intense, but this methodology captures successfully the context of technology deployment and allows decision-making based on a robust and democratic process, which addresses uncertainties, acknowledges multiple legitimate perspectives and encourages social learning.Participatory multi-criteria analysis Energy scenarios Renewable energy Sustainable development

The Influence of Social Preferences on Multi-Criteria Evaluation of Energy Scenarios

Participatory multi-criteria evaluation (MCE) is increasingly used for the integrated assessment of future scenarios. Determining weights of the different criteria constitutes one of the biggest challenges of MCE. This paper investigates the influence of weights on the ranking of scenarios and reflects critically on the use of weights as representations of social preferences in participatory MCE. Conceptually, this exercise builds on the literature on integrated assessment and decision making under uncertainty; empirically, insights are drawn from two case studies of renewable energy scenario assessment for Austria at the national and local level. The analysis exhibits a robust ranking for the local level, especially for the highest ranked scenarios. In the national case study, the analysis finds two robust scenario clusters which never switch ranks, whereas the ranking of the scenarios within the clusters flips with minor alters in weights. This paper argues that in participatory MCE different sets of stakeholders' priorities can be taken into account in a transparent and robust manner. The discussion explores inhowfar weights represent social preferences better than direct ranking of alternative scenarios by stakeholders on the basis of scenario presentations.social preferences; participatory multi-criteria evaluation; renewable energy; scenario analysis; sustainable energy systems