1,372 research outputs found
2. Wochenbericht TRR 181 Cruise Poseidon 523 [POS523]
2 â 23 May 2018, Malaga - Ponto Delgad
3. Wochenbericht TRR 181 Cruise Poseidon 523 [POS523]
2 â 23 May 2018, Malaga - Ponto Delgad
2. Wochenbericht TRR 181 Cruise Poseidon 523 [POS523]
2 â 23 May 2018, Malaga - Ponto Delgad
1. Wochenbericht TRR 181 Cruise Poseidon 523 [POS523]
2 â 23 May 2018, Malaga - Ponto Delgad
NearâInertial Wave Propagation in the Deep Canadian Basin: Turning Depths and the Homogeneous Deep Layer
The internal wave climate in the deep Arctic Ocean, away from the shelves, is quiet because the ice cover shields the ocean from wind energy input, and tidal amplitudes are small. Hence, mixing due to internal wave breaking is small. The shrinking Arctic sea ice cover, however, exposes more open ocean areas to energy transfer by wind. Consequently, more energetic near-inertial internal waves (NIWs) may carry energy to the bottom, potentially enhancing deep mixing. In the deep Canadian Basin, weakly stratified layers with local buoyancy frequencies smaller than the wave frequency may prevent NIW propagation to the seafloor. We estimate the distribution of these near-inertial turning depths from temperature and salinity data of the years 2005â2014. Near-inertial turning depths are ubiquitous in the deep Canadian Basin at âŒ2,750 m depth, between 100 and 1,200 m above the bottom. A deep homogeneous layer below 3,300 m is characterized by small squared buoyancy frequencies N2 âŒÂ 0 with locally unstable layers (N2 < 0). The turning depths reflect NIWs and hence limit their contribution to deep mixing, but the waves create an evanescent perturbation with exponentially decreasing amplitude that can interact with the bathymetry, especially above slopes and ridges where the height of the turning depths above the seafloor is small. After reflection, the main part of the wave energy is trapped between turning depths and the surface, so that a potential increase of wave energy input mainly affects mixing of mid-depth water masses like the Atlantic Water
Comparison of tools for assessing the methodological quality of primary and secondary studies in health technology assessment reports in Germany
Health care policy background: Findings from scientific studies form the basis for evidence-based health policy decisions. Scientific background: Quality assessments to evaluate the credibility of study results are an essential part of health technology assessment reports and systematic reviews. Quality assessment tools (QAT) for assessing the study quality examine to what extent study results are systematically distorted by confounding or bias (internal validity). The tools can be divided into checklists, scales and component ratings. Research questions: What QAT are available to assess the quality of interventional studies or studies in the field of health economics, how do they differ from each other and what conclusions can be drawn from these results for quality assessments? Methods: A systematic search of relevant databases from 1988 onwards is done, supplemented by screening of the references, of the HTA reports of the German Agency for Health Technology Assessment (DAHTA) and an internet search. The selection of relevant literature, the data extraction and the quality assessment are carried out by two independent reviewers. The substantive elements of the QAT are extracted using a modified criteria list consisting of items and domains specific to randomized trials, observational studies, diagnostic studies, systematic reviews and health economic studies. Based on the number of covered items and domains, more and less comprehensive QAT are distinguished. In order to exchange experiences regarding problems in the practical application of tools, a workshop is hosted. Results: A total of eight systematic methodological reviews is identified as well as 147 QAT: 15 for systematic reviews, 80 for randomized trials, 30 for observational studies, 17 for diagnostic studies and 22 for health economic studies. The tools vary considerably with regard to the content, the performance and quality of operationalisation. Some tools do not only include the items of internal validity but also the items of quality of reporting and external validity. No tool covers all elements or domains. Design-specific generic tools are presented, which cover most of the content criteria. Discussion: The evaluation of QAT by using content criteria is difficult, because there is no scientific consensus on the necessary elements of internal validity, and not all of the generally accepted elements are based on empirical evidence. Comparing QAT with regard to contents neglects the operationalisation of the respective parameters, for which the quality and precision are important for transparency, replicability, the correct assessment and interrater reliability. QAT, which mix items on the quality of reporting and internal validity, should be avoided. Conclusions: There are different, design-specific tools available which can be preferred for quality assessment, because of its wider coverage of substantive elements of internal validity. To minimise the subjectivity of the assessment, tools with a detailed and precise operationalisation of the individual elements should be applied. For health economic studies, tools should be developed and complemented with instructions, which define the appropriateness of the criteria. Further research is needed to identify study characteristics that influence the internal validity of studies
Mediastinal widening on chest radiography caused by combined aortic valve disease and primary large B-cell lymphoma
Poststenotic aortic root dilatation in patients with aortic valvular stenosis may result in
mediastinal widening on chest radiograph. Main differential diagnosis of mediastinal
widening is a tumour. In fact, besides atypical chest pain or dyspnoea at exertion
secondary to compression of intrathoracic structures in the latter, symptoms may be
absent. This article reports a case of combined aortic valve disease and additional primary
large B-cell lymphoma.peer-reviewe
Interventions for increasing uptake in screening programmes
Introduction: Opportunities for the early detection of disease are not sufficiently being taken advantage of. Specific interventions could increase the uptake of prevention programmes. A comprehensive analysis of effectiveness and cost-effectiveness of these interventions with reference to Germany is still needed. Objectives: This report aimed to describe and assess interventions to increase uptake in primary and secondary prevention and to explore the assessment of their cost-effectiveness. Methods: 29 scientific databases were systematically searched in a wide strategy. Additional references were located from bibliographies. All published systematic reviews and primary studies were assessed for inclusion without language restrictions. Teams of two reviewers identified the literature, extracted data and assessed the quality of the publications independently. Results: Four HTA reports and 22 systematic reviews were identified for the medical evaluation covering a variety of interventions. The economic evaluation was based on two HTA-reports, one meta-analysis and 15 studies. The evidence was consistent for the effectiveness of invitations and reminders aimed at users, and for prompts aimed at health care professionals. These interventions were the most commonly analysed. (Financial) Incentives for users and professionals were identified in a small number of studies. Limited evidence was available for cost-effectiveness showing incremental costs for follow-up reminders and invitations by telephone. Evidence for ethical, social and legal aspects pointed to needs in vulnerable populations. Discussion: The material was heterogeneous regarding interventions used, study populations and settings. The majority of references originated from the United States and focused on secondary prevention. Approaching all target groups by invitations and reminders was recommended to increase uptake in prevention programmes in general. Conclusions: Further research should aim to focus on primary prevention. Future research should also focus on specific interventions aiming to include vulnerable target groups and individuals, who have not previously made use of opportunities for prevention
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