13 research outputs found
Neo-Atlantis: Dutch Responses to Five Meter Sea Level Rise
What would happen to the Netherlands if, in 2030, the sea level starts to rise and eventually, after 100 years, a sea level of five meters above current level would be reached? Two socio-economic scenarios are developed from a literature review and by interviews with researchers and practicionersin the domains of social sciences, economics, civil engineering, and land use planning. One scenario describes what would happen in a future characterised by a trend towards further globalisation, marketisation and high economic growth, while the other scenario happens in a future under opposite trends. Under both scenarios, the Southwest and Northwest of the Netherlands – already now below seal level - would be abandoned because of sea level rise. Although most experts believe that geomorphology and current engineering skills allow to largely maintain the territorial integrity of the Netherlands, there are some reasons to assume that this is not likely to happen. Social processes that precede important political decisions – such as the growth of the belief in the reality of SLR and the framing of such decision in a proper political context (policy window) – evolve slowly. Although a flood disaster would speed up decision-making, the general expectation is that decisions would come too late in view of the rate of SLR and the possible pace of construction of works.Extreme sea level rise, The Netherlands, flood defences
Adapting to climate: A case study on riverine flood risks in The Netherlands
Climate change may well lead to an increased risk of river floods in the Netherlands. However, the impacts of changes in water management on river floods are larger, either enhancing or reducing flood risks. Therefore, the abilities of water-management authorities to learn that climate and river flows are changing, and to recognize and act upon the implications, are of crucial importance. At the same time, water-management authorities respond to other trends, such as the democratization of decision making, which alter their ability to react to climate change. These complex interactions are illustrated with changes in river flood risk management for the Rhine and the Meuse in the Netherlands over the last 50 years. A scenario study is used to seek insight into the question of whether current water-management institutions and their likely successors are capable of dealing with plausible future flood risks. The scenarios show that new and major infrastructure is needed to keep flood risks at their current level. Such a structural solution to future flood risks is feasible, but requires considerable political will and institutional reform, both for planning and implementation. It is unlikely that reform will be fast enough or the will strong enough
Antithrombotic therapy after mitral valve repair: VKA or aspirin?
The optimal antithrombotic therapy following mitral valve repair (MVr) is still a matter of debate. Therefore, we evaluated the rate of thromboembolic and bleeding complications of two antithrombotic prevention strategies: vitamin K antagonists (VKA) versus aspirin. Consecutive patients who underwent MVr between 2004 and 2016 at three Dutch hospitals were evaluated for thromboembolic and bleeding complications during three postoperative months. The primary endpoint was the combined incidence of thromboembolic and bleeding complications to determine the net clinical benefit of VKA strategy as compared with aspirin. Secondary objectives were to evaluate both thromboembolic and bleeding rates separately and to identify predictors for both complications. A total of 469 patients were analyzed, of whom 325 patients (69%) in the VKA group and 144 patients (31%) in the aspirin group. Three months postoperatively, the cumulative incidence of the combined end point of the study was 9.2% (95%CI 6.1–12) in the VKA group and 11% (95%CI 6.0–17) in the aspirin group [adjusted hazard ratio (HR) 1.6, 95%CI 0.83–3.1]. Moreover, no significant differences were observed in thromboembolic rates (adjusted HR 0.82, 95%CI 0.16–4.2) as well as in major bleeding rates (adjusted HR 1.89, 95%CI 0.90–3.9). VKA and aspirin therapy showed a similar event rate of 10% during 3 months after MVr in patients without prior history of AF. In both treatment groups thromboembolic event rate was low and major bleeding rates were comparable. Future prospective, randomized trials are warranted to corroborate our findings
Correction to: Antithrombotic therapy after mitral valve repair: VKA or aspirin? (Journal of Thrombosis and Thrombolysis, (2018), 46, 4, (473-481), 10.1007/s11239-018-1724-0)
The original version of this article unfortunately contained a mistake in the author name. The co-author name should be Frederikus A. Klok instead of Frederik A. Klok. The original article has been corrected
Functional characterization of UDP-glucose:undecaprenyl-phosphate glucose-1-phosphate transferases of Escherichia coli and Caulobacter crescentus
Escherichia coli K-12 WcaJ and the Caulobacter crescentus HfsE, PssY, and PssZ enzymes are predicted to initiate the synthesis of colanic acid (CA) capsule and holdfast polysaccharide, respectively. These proteins belong to a prokaryotic family of membrane enzymes that catalyze the formation of a phosphoanhydride bond joining a hexose-1-phosphate with undecaprenyl phosphate (Und-P). In this study, in vivo complementation assays of an E. coli K-12 wcaJ mutant demonstrated that WcaJ and PssY can complement CA synthesis. Furthermore, WcaJ can restore holdfast production in C. crescentus. In vitro transferase assays demonstrated that both WcaJ and PssY utilize UDP-glucose but not UDP-galactose. However, in a strain of Salmonella enterica serovar Typhimurium deficient in the WbaP O antigen initiating galactosyltransferase, complementation with WcaJ or PssY resulted in O-antigen production. Gas chromatography-mass spectrometry (GC-MS) analysis of the lipopolysaccharide (LPS) revealed the attachment of both CA and O-antigen molecules to lipid A-core oligosaccharide (OS). Therefore, while UDP-glucose is the preferred substrate of WcaJ and PssY, these enzymes can also utilize UDP-galactose. This unexpected feature of WcaJ and PssY may help to map specific residues responsible for the nucleotide diphosphate specificity of these or similar enzymes. Also, the reconstitution of O-antigen synthesis in Salmonella, CA capsule synthesis in E. coli, and holdfast synthesis provide biological assays of high sensitivity to examine the sugar-1-phosphate transferase specificity of heterologous proteins
A highly structured,nuclease-resistant, noncoding RNA produced by flaviviruses is required for pathogenicity
Viral noncoding RNAs have been shown to play an important role in virus-host interplay to facilitate virus replication. We report that members of the genus Flavivirus, a large group of medically important encephalitic RNA viruses, produce a unique and highly structured noncoding RNA of 0.3–0.5 kb derived from the 3′ untranslated region of the viral genome. Using West Nile virus as a model, we show that this subgenomic RNA is a product of incomplete degradation of viral genomic RNA by cellular ribonucleases. Highly conserved RNA structures located at the beginning of the 3′ untranslated region render this RNA resistant to nucleases, and the resulting subgenomic RNA product is essential for virus-induced cytopathicity and pathogenicity. Thus, flaviviruses evolved a unique strategy to generate a noncoding RNA product that allows them to kill the host more efficiently