Numerical modelling of the extreme wave climate in the Belgian harbours: part 3. Marina of Blankenberge

The design of water and wave retaining walls and flood risk analyses need hydrodynamic boundary conditions. These boundary conditions are needed during a storm with return period 1000yrs and during the super storms which were defined in the risk analysis study. The modelling of the extreme wave climate is decoupled to the wave penetration and the lacal generation of waves by the extreme wind speed. The wave penetration is modelled with Mike 21 BW as was done for Oostende and Zeebrugge. MILDwave is not used this time because non-linear effects (e.g. long wave generation, wave setup) are too important in this case. Instead another nonlinear model SWASH is applied. The modelling of local generation of waves by wind is still done with the spectral model SWAN.First the bathymetry files are created based on the dredging plan of Blankenberge marina, and all the suitable settings used for the Mike 21 BW and the SWASH are investigated. Since SWASH model does not have so much application examples, Wenduine physical model is used to validate the model. Consequently, a sensitivity analysis is conducted for both models to study which parameter is important for the wave climate inside the marina. The most severe offshore wave direction for the design of the wave retaining walls is decided based on the 1000 year storm. After the calculation of the wave penetration in the case of 1000 year storm and +7.9 mTAW storm, locally generated wind waves are also simulated by SWAN. All extreme wind speeds and directions for the 1000-year storm and the super storms are modelled. Finally, long and short wave energy of the wave penetration models is separated and a superposition of the short wave energy and the SWAN model is done to obtain the total extreme wave climate in the marina of Blankenberge. The maximum surface elevation of the long wave energy and the wave setup provide an increase of the still water level to take into account for design purpose

2D overtopping and impact experiments in shallow foreshore conditions

This paper introduces the 2D experiments conducted for the CREST project in the wave flume of Ghent University. The experiments focus on wave interactions with low-crested sea dikes fronted by a shallow foreshore and mildly to steeply sloping beaches, which is a very typical situation along the Belgian coast. Foreshore slopes of 1/20, 1/35, 1/50 and 1/80 were tested for a range of low to high energy wave conditions, a variation in wave steepness and two water levels. The main goal was to obtain a dataset in which the effects of the infragravity waves on the wave-structure interactions (i.e. wave overtopping and impact forces) can be studied. The tests included high spatial resolution surface elevation measurement tests, which is new for beaches including a dike in the inner surf zone. From the first results it became clear that the foreshore slope influences the wave transformation up to the dike toe. The influence is apparent comparing to existing (semi-) empirical models for prediction of the spectral wave period at the dike toe and wave overtopping at the dike crest. The high spatial resolution data show a steep increase in infragravity significant wave height in the very shallow area in front of the dike

Egg Laying Decisions in Drosophila Are Consistent with Foraging Costs of Larval Progeny

Decision-making is defined as selection amongst options based on their utility, in a flexible and context-dependent manner. Oviposition site selection by the female fly, Drosophila melanogaster, has been suggested to be a simple and genetically tractable model for understanding the biological mechanisms that implement decisions [1]. Paradoxically, female Drosophila have been found to avoid oviposition on sugar which contrasts with known Drosophila feeding preferences [1]. Here we demonstrate that female Drosophila prefer egg laying on sugar, but this preference is sensitive to the size of the egg laying substrate. With larger experimental substrates, females preferred to lay eggs directly on sugar containing media over other (plain, bitter or salty) media. This was in contrast to smaller substrates with closely spaced choices where females preferred non-sweetened media. We show that in small egg laying chambers newly hatched first instar larvae are able to migrate along a diffusion gradient to the sugar side. In contrast, in contexts where females preferred egg laying directly on sugar, larvae were unable to migrate to find the sucrose if released on the sugar free side of the chamber. Thus, where larval foraging costs are high, female Drosophila choose to lay their eggs directly upon the nutritious sugar substrate. Our results offer a powerful model for female decision-making

Chemotherapeutic errors in hospitalised cancer patients: attributable damage and extra costs

<p>Abstract</p> <p>Background</p> <p>In spite of increasing efforts to enhance patient safety, medication errors in hospitalised patients are still relatively common, but with potentially severe consequences. This study aimed to assess antineoplastic medication errors in both affected patients and intercepted cases in terms of frequency, severity for patients, and costs.</p> <p>Methods</p> <p>A 1-year prospective study was conducted in order to identify the medication errors that occurred during chemotherapy treatment of cancer patients at a French university hospital. The severity and potential consequences of intercepted errors were independently assessed by two physicians. A cost analysis was performed using a simulation of potential hospital stays, with estimations based on the costs of diagnosis-related groups.</p> <p>Results</p> <p>Among the 6, 607 antineoplastic prescriptions, 341 (5.2%) contained at least one error, corresponding to a total of 449 medication errors. However, most errors (n = 436) were intercepted before medication was administered to the patients. Prescription errors represented 91% of errors, followed by pharmaceutical (8%) and administration errors (1%). According to an independent estimation, 13.4% of avoided errors would have resulted in temporary injury and 2.6% in permanent damage, while 2.6% would have compromised the vital prognosis of the patient, with four to eight deaths thus being avoided. Overall, 13 medication errors reached the patient without causing damage, although two patients required enhanced monitoring. If the intercepted errors had not been discovered, they would have resulted in 216 additional days of hospitalisation and cost an estimated annual total of 92, 907€, comprising 69, 248€ (74%) in hospital stays and 23, 658€ (26%) in additional drugs.</p> <p>Conclusion</p> <p>Our findings point to the very small number of chemotherapy errors that actually reach patients, although problems in the chemotherapy ordering process are frequent, with the potential for being dangerous and costly.</p

DÉTERMINISME DE LA DURÉE DE DÉVELOPPEMENT CHEZ DROSOPHILA MELANOGASTER

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