160 research outputs found
De vernatting van Nederland: het gevolg van een toename van de extreme neerslag?
No full textDe laatste jaren wordt er steeds meer aandacht besteed de wereldwijde klimaatverandering die een gevolg zou kunnen zijn van een versterkt broeikaseffect. Er zijn talloze aanwijzingen te vinden die wijzen op een verandering van het klimaat. Verwoestijning in Afrika en grootschalige overstromingen in Europa (Tsjechië, Oost-Duitsland, Noord-Frankrijk, België en ook Nederland kampten in 2002 met ernstige wateroverlast) zijn de sprekende voorbeelden die de wetenschappelijke wereld aan het denken zetten. Ook in Nederland is de afgelopen eeuw de neerslaghoeveelheid toegenomen. Vooral extreme buien worden steeds vaker waargenomen. Dat levert vaak schade op, zoals bij de Ikea waar op 24 augustus 2002 een dak onder het gewicht van het water bezweek tijdens een hevige bui. Op dezelfde dag stortte het dak van de zwembaden in Weesp en Ettenleur in. Dit artikel bespreekt de veranderingen in het neerslagklimaat van Nederland aan de hand van 100 jaar neerslaggegevens. Het blijkt dat de toename van de gemiddelde jaarlijkse neerslag komt doordat het vaker regent en deels doordat de neerslagintensiteit toegenomen is
Fault analysis and improved design of JET in-vessel Mirnov coils
No full textIn vessel Mirnov coils are an essential diagnostic in present day tokamaks. Their use in ITER and future Fusion reactors presents some disadvantages linked to the high radiation environment. Furthermore large Electro Magnetic (EM) forces can be experienced by the coil, due to the pulsed operation of the tokamak device (Van Nieuwenhove and Vermeeren, 2003, Vayakis et al., 2011 [1,2]), and disruptions (Gerasimov et al., 2015 [3]). Since the operation with the ITER-like wall, JET has experienced severe faults in the high-bandwidth Ti wire coils. During 2016-17 new coils have been designed and installed. These can be replaced using remote handling, and they use Cu alloy wire. The presented work includes the failure analysis and modelling, motivating the design differences between old and new coils. The latter will provide valuable information on the long term effects of EM loads during disruptions, as well as chemical degradation processes that will be encountered for ITER High Frequency (HF) coils, which are characterized by the same materials
Understanding the Book of Job: 11Q10, the Peshitta and the Rabbinic Targum. Illustrations from a synoptic analysis of Job 37-39
No full textThis synoptic analysis of verses from Job chapters 37-39 in 11Q10, the Peshitta version (PJob) and the rabbinic targum (RJob) aims to identify the translators’ methods for handling the Hebrew text (HT) and to assess the apparent skills and knowledge brought by them to their task. Additionally, the study engages with recent discussion which challenges the nature of 11Q10 as targum. To this end, PJob and RJob provide accepted models of ‘translation’ and ‘targum’ alongside which to assess 11Q10. The following translation methods are identified, described, compared and contrasted in the three versions: selection,extension, alternative translation, expansion, substitution, adjustment of the consonantal HT, adjustment of the Hebrew word order or division, omission, and conjecture. PJob is confirmed as an attempt to transpose the difficult Hebrew of Job into Syriac. RJob is confirmed as a conservative translation with clear underpinnings in allusion to scripture and to rabbinic traditions attested elsewhere. Significant observations are made regarding an interpretative quality in 11Q10, and new light is cast on its richness and subtlety as an allusive translation. It is proposed that the translation displays deep knowledge of scripture and skill in applying this knowledge. It is further proposed that careful comparison with methods which have been identified in Onqelos is warranted. 11Q10 is identified as an important early witness to scripturally-based motifs which are also found in other intertestamental and rabbinic sources. It is argued that 11Q10’s nature suggests that its purpose was not simply to translate but to understand and subtly explicate the HT, and that it was intended for use alongside it, not as a replacement. The study refutes the categorization of 11Q10 as ‘translation’ rather than ‘targum’, and agrees with its orginal editors that its value lies in its unique witness to the early nature of targum
Duodenal lipid-induced symptom generation in gastroesophageal reflux disease: Role of apolipoprotein A-IV and cholecystokinin
No full textBackground Duodenal lipid intensifies the perception of esophageal acid perfusion. Recently, we showed that genes implicated in lipid absorption were upregulated in the duodenum of fasting gastro-esophageal reflux disease (GERD) patients. This suggests that chylomicron production and secretion may be enhanced and, consequently, the release of apolipoprotein A-IV (apoA-IV), a chylomicron-derived signaling protein. ApoA-IV may stimulate release of cholecystokinin (CCK), an activator of vagal afferents. This study evaluated putative involvement of abnormal apoA-IV and CCK responses to lipid in GERD.Methods Ten GERD patients and 10 healthy volunteers (HV) underwent duodenal perfusion with Intralipid 20%, 2 kcal min(-1) , for 60 min. Symptoms were scored, blood samples collected every 15 min during lipid perfusion and 15 min after discontinuation when duodenal biopsies were taken. Plasma and mucosal concentrations of apoA-IV and CCK and transcript levels of 21 genes implicated in lipid absorption, differentially expressed under fasting conditions, were quantified.Key results Heartburn (P = 0.003), abdominal discomfort (P = 0.037) and nausea (P = 0.008) only increased significantly during lipid infusion in GERD patients. Following lipid infusion mean mucosal apoA-IV concentration was lower in GERD patients compared with HV (P = 0.023), whereas plasma concentration tended to be elevated (P = 0.068). Mean mucosal CCK concentration was also lower in GERD patients (P = 0.009). Two genes, HIBADH and JTB, were upregulated in GERD patients (P = 0.008 and P = 0.038, respectively).Conclusions & inferences Our results suggest excessive duodenal lipid-induced release of apoA-IV and CCK in GERD. We postulate that the resulting heightened activation of duodenal vagal afferents may underlie central sensitization, thereby increasing the perception of reflux events.O. S. Van Boxel, J. J. M. Ter Linde, J. Oors, B. Otto, C. Feinle-Bisset, A. J. P. M. Smout & P. D. Siersem
Functional dyspepsia patients have lower mucosal cholecystokinin concentrations in response to duodenal lipid
No full textBACKGROUND: Dyspeptic symptoms are frequently induced, or exacerbated, by fatty food ingestion. Excessive release of, and/or hypersensitivity to, cholecystokinin (CCK) may explain the exaggerated response to lipid in patients with functional dyspepsia (FD). Thus far, plasma CCK response has been evaluated. However, stimulation of CCK1 receptors on duodenal vagal afferents occurs in a paracrine manner, suggesting that mucosal CCK concentrations are relevant to quantify. Apolipoprotein A-IV stimulates mucosal CCK release. AIM: To investigate the hypothesis that fat-induced release of CCK and apolipoprotein A-IV (apoA-IV) is enhanced in the duodenum of FD patients. PATIENTS AND METHODS: Sixteen symptomatic FD patients and 10 healthy volunteers (HV) underwent duodenal perfusion with intralipid 20%, 2 kcal/min, for 60 min. Symptoms were scored and blood samples were collected every 15 min during lipid perfusion and 15 min after discontinuation when duodenal biopsies were taken. Plasma and mucosal concentrations of CCK and apoA-IV were quantified. RESULTS: Abdominal discomfort (P=0.001), nausea (P=0.05), and fullness (P=0.005) in response to duodenal lipid increased significantly only in FD patients. Following lipid infusion, the mean mucosal CCK concentration was lower in FD patients compared with HV (P<0.0001). Fasting concentrations and plasma response of CCK were comparable in FD patients and HV. Plasma apoA-IV response appeared to differ between patients and HV, whereas mucosal apoA-IV concentrations were similar. CONCLUSION: Our results suggest excessive local release of CCK in response to duodenal lipid in FD. This likely causes exaggerated stimulation of duodenal vagal afferents, explaining dyspeptic symptom generation. The mechanisms underlying elevated mucosal CCK release warrant further investigation.Ofke S. van Boxel, Jose, J.M. ter Linde, Jac Oors, Bärbel Ottoc, Bas L.A.M. Weusten, Christine Feinle-Bisset, André J.P.M. Smout and Peter D. Siersem
Wind Velocity and Algal Crusts in Dune Blowouts
No full textIn two saucer-shaped blowouts wind velocity was measured at 0.18 m height and compared to the wind velocity data from the nearest standard meteorological station at Valkenburg about 3.5 km to the northeast. In blowout 1 relative velocities are highest when the wind blows from directions between E and SSE. In blowout 2 winds blowing from directions between S and WSW are relatively stronger. In general the wind speed increases as its moves along the surface inside the blowout, because the aerodynamic roughness of the blowout surface is less than that of the surrounding area. Less important are the influence of the configuration of the terrain surrounding the blowout and the influence of the slopes within the blowout. The frequency distribution of the general wind at Valkenburg is analysed and combined with the horizontal wind velocity pattern within blowouts. A simulation model, producing the spatial distribution of the wind power shows that the prevalence of algal crusts at the SW side of blowouts agrees well with the location which reaches the lowest wind power values. In other parts of the blowouts algal crusts are damaged by moving sand at times of high wind velocity
Programmeringsstudie Alternatieven voor Dieproeven - Deel 2 : Samen vervangen, verminderen en verfijnen
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Machine learning to predict early recurrence after oesophageal cancer surgery
No full textBackground: Early cancer recurrence after oesophagectomy is a common problem, with an incidence of 20–30 per cent despite the widespread use of neoadjuvant treatment. Quantification of this risk is difficult and existing models perform poorly. This study aimed to develop a predictive model for early recurrence after surgery for oesophageal adenocarcinoma using a large multinational cohort and machine learning approaches. Methods: Consecutive patients who underwent oesophagectomy for adenocarcinoma and had neoadjuvant treatment in one Dutch and six UK oesophagogastric units were analysed. Using clinical characteristics and postoperative histopathology, models were generated using elastic net regression (ELR) and the machine learning methods random forest (RF) and extreme gradient boosting (XGB). Finally, a combined (ensemble) model of these was generated. The relative importance of factors to outcome was calculated as a percentage contribution to the model. Results: A total of 812 patients were included. The recurrence rate at less than 1 year was 29·1 per cent. All of the models demonstrated good discrimination. Internally validated areas under the receiver operating characteristic (ROC) curve (AUCs) were similar, with the ensemble model performing best (AUC 0·791 for ELR, 0·801 for RF, 0·804 for XGB, 0·805 for ensemble). Performance was similar when internal–external validation was used (validation across sites, AUC 0·804 for ensemble). In the final model, the most important variables were number of positive lymph nodes (25·7 per cent) and lymphovascular invasion (16·9 per cent). Conclusion: The model derived using machine learning approaches and an international data set provided excellent performance in quantifying the risk of early recurrence after surgery, and will be useful in prognostication for clinicians and patients.</p
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