59 research outputs found

    Receptief, productief, en receptief+productief woorden leren: Wat maakt het uit?

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    De centrale vraag in dit artikel hoe woorden in een vreemde taal het best geleerd kunnen worden: als je woorden in een vreemde taal receptief moet kennen, van de vreemde taal naar de moedertaal, moet je ze dan alleen receptief leren, of heeft het zin om ze ook ze ook productief te leren omdat je ze dan wellicht beter onthoudt? Deze praktijkvraag vormde het uitgangspunt voor het leerexperiment waarvan Jan-Arjen Mondria en Boukje Wiersma in dit artikel verslag doen. Daarbij bleek, in afwijking van de verwachting, dat het zowel receptief als productief leren van woorden tot een vergelijkbare receptieve retentie leidde als receptief leren alleen. Eveneens onverwacht leidde het zowel productief als receptief leren tot een vergelijkbare productieve retentie als productief leren alleen

    Local and average fields inside surface-disordered waveguides: Resonances in the one-dimensional Anderson localization regime

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    We investigate the one-dimensional propagation of waves in the Anderson localization regime, for a single-mode, surface disordered waveguide. We make use of both an analytical formulation and rigorous numerical simulation calculations. The occurrence of anomalously large transmission coefficients for given realizations and/or frequencies is studied, revealing huge field intensity concentration inside the disordered waveguide. The analytically predicted s-like dependence of the average intensity, being in good agreement with the numerical results for moderately long systems, fails to explain the intensity distribution observed deep in the localized regime. The average contribution to the field intensity from the resonances that are above a threshold transmission coefficient TcT_{c} is a broad distribution with a large maximum at/near mid-waveguide, depending universally (for given TcT_{c}) on the ratio of the length of the disorder segment to the localization length, L/ξL/\xi. The same universality is observed in the spatial distribution of the intensity inside typical (non-resonant with respect to the transmission coefficient) realizations, presenting a s-like shape similar to that of the total average intensity for TcT_{c} close to 1, which decays faster the lower is TcT_{c}. Evidence is given of the self-averaging nature of the random quantity log[I(x)]/x1/ξ\log[I(x)]/x\simeq -1/\xi. Higher-order moments of the intensity are also shown.Comment: 9 pages, 9 figure

    Acute kidney injury after the arterial switch operation: incidence, risk factors, and outcomes

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    Background: The aim of this retrospective cohort study was to determine the incidence, potential risk factors, characteristics, and outcomes of acute kidney injury in children following the arterial switch operation for transposition of the great arteries. Methods: Retrospective review of children who underwent ASO between 2000 and 2020 in our tertiary children's hospital in the Netherlands. Pre-and post-ASO serum creatinine levels were collected. Severe AKI was defined as 100% serum creatinine rise or estimated creatinine clearance Results: A total of 242 children were included. Fifty-seven (24%) children developed severe AKI after ASO. Four patients with severe AKI were treated with renal replacement therapy. Children with severe AKI had a longer duration of mechanical ventilation 4.5 (1.0-29) versus 3 (1.0-12) days (p = 0.001), longer PICU stay 7 (2-76) versus 5 (1-70) days, (p = 0.001), higher rate of myocardial infarction 5% versus 0.5% (p = 0.001), sepsis 24% versus 9% (p = 0.002), post-operative pulmonary hypertension 19% versus 6% (p = 0.002), post-operative bleeding 9% versus 3% (p = 0.044), longer time to sternal closure 3 (1-19) versus 2 (1-6) days, (p = 0.009), and a higher mortality rate 9.0% versus 0.5% (p = 0.001) compared to children without severe AKI. Sepsis was a risk factor for developing severe AKI. Conclusions: In this single-centre cohort, 24% of our patients developed severe AKI after ASO, which is associated with increased morbidity, longer PICU stay, and higher mortality.Thoracic Surger

    Quasi Two-dimensional Transfer of Elastic Waves

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    A theory for multiple scattering of elastic waves is presented in a random medium bounded by two ideal free surfaces, whose horizontal size is infinite and whose transverse size is smaller than the mean free path of the waves. This geometry is relevant for seismic wave propagation in the Earth crust. We derive a time-dependent, quasi-2D radiative transfer equation, that describes the coupling of the eigenmodes of the layer (surface Rayleigh waves, SH waves, and Lamb waves). Expressions are found that relate the small-scale fluctuations to the life time of the modes and to their coupling rates. We discuss a diffusion approximation that simplifies the mathematics of this model significantly, and which should apply at large lapse times. Finally, coherent backscattering is studied within the quasi-2D radiative transfer equation for different source and detection configurations.Comment: REVTeX, 36 pages with 10 figures. Submitted to Phys. Rev.

    Een robuust en maatschappelijk gedragen energiesysteem MMIP 13

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    De energietransitie zal de komende decennia grote veranderingen teweeg brengen in onze maatschappij. Industrie, gebouwde omgeving, landbouw, mobiliteit en de energiesector zullen grootschalig gaan verduurzamen. Verduurzamingstrajecten kennen echter veel onzekerheden en zijn vaak afhankelijk van elkaar. Deze complexiteit krijgt nog een extra dimensie omdat er ook afhankelijkheden zijn tussen de verschillende sectoren. De energietransitie is niet alleen een technologisch vraagstuk, maar is ook sociaal economisch, maatschappelijk, ruimtelijk en ecologisch van aard. Voor deze systeemproblematiek is vaak geen eenduidige eigenaar. In dit proces speelt het energiesysteem een centrale rol. Het zal de komende jaren een fundamentele verandering ondergaan: fossiele brandstoffen zullen stap voor stap worden vervangen door grote hoeveelheden duurzame, (intermitterende) bronnen, de vraag naar energie zal gaan veranderen, de grenzen tussen energiedragers zullen vervagen, er zullen (onderling verbonden) energiesystemen ontstaan op alle schaalniveaus (woning, wijk, regio, nationaal, internationaal), nieuwe spelers zullen in de energiemarkt hun intrede doen. Kortom het energiesysteem wordt steeds complexer. Dit betekent dat een transitieproces nodig is dat het mogelijk maakt om, vanuit een systeemperspectief, adequaat, hoogwaardig en efficiënt besluiten te kunnen nemen over en invulling te geven aan de inrichting en werking van een betaalbaar en geaccepteerd energiesysteem waarbij de betrouwbaarheid, leveringszekerheid en veiligheidop het zelfde niveau blijven als vandaag de dag. Het Meerjarig Missiegedreven InnovatieProgramma (MMIP) 13 ontwikkelt hiervoor kennis en innovaties. De 6 deelprogramma’s van dit MMIP richten zich op verschillende aspecten van de uitdaging rond het integrale energiesysteem. Het programma kent zowel technische als economische en sociale aspecten

    Improving Genetic Prediction by Leveraging Genetic Correlations Among Human Diseases and Traits

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    Genomic prediction has the potential to contribute to precision medicine. However, to date, the utility of such predictors is limited due to low accuracy for most traits. Here theory and simulation study are used to demonstrate that widespread pleiotropy among phenotypes can be utilised to improve genomic risk prediction. We show how a genetic predictor can be created as a weighted index that combines published genome-wide association study (GWAS) summary statistics across many different traits. We apply this framework to predict risk of schizophrenia and bipolar disorder in the Psychiatric Genomics consortium data, finding substantial heterogeneity in prediction accuracy increases across cohorts. For six additional phenotypes in the UK Biobank data, we find increases in prediction accuracy ranging from 0.7 for height to 47 for type 2 diabetes, when using a multi-trait predictor that combines published summary statistics from multiple traits, as compared to a predictor based only on one trait. © 2018 The Author(s)

    Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications

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    BACKGROUND Limited information exists about the epidemiology and outcome of surgical patients at increased risk of postoperative pulmonary complications (PPCs), and how intraoperative ventilation was managed in these patients. OBJECTIVES To determine the incidence of surgical patients at increased risk of PPCs, and to compare the intraoperative ventilation management and postoperative outcomes with patients at low risk of PPCs. DESIGN This was a prospective international 1-week observational study using the ‘Assess Respiratory Risk in Surgical Patients in Catalonia risk score’ (ARISCAT score) for PPC for risk stratification. PATIENTS AND SETTING Adult patients requiring intraoperative ventilation during general anaesthesia for surgery in 146 hospitals across 29 countries. MAIN OUTCOME MEASURES The primary outcome was the incidence of patients at increased risk of PPCs based on the ARISCAT score. Secondary outcomes included intraoperative ventilatory management and clinical outcomes. RESULTS A total of 9864 patients fulfilled the inclusion criteria. The incidence of patients at increased risk was 28.4%. The most frequently chosen tidal volume (VT) size was 500 ml, or 7 to 9 ml kg1 predicted body weight, slightly lower in patients at increased risk of PPCs. Levels of positive end-expiratory pressure (PEEP) were slightly higher in patients at increased risk of PPCs, with 14.3% receiving more than 5 cmH2O PEEP compared with 7.6% in patients at low risk of PPCs (P < 0.001). Patients with a predicted preoperative increased risk of PPCs developed PPCs more frequently: 19 versus 7%, relative risk (RR) 3.16 (95% confidence interval 2.76 to 3.61), P < 0.001) and had longer hospital stays. The only ventilatory factor associated with the occurrence of PPCs was the peak pressure. CONCLUSION The incidence of patients with a predicted increased risk of PPCs is high. A large proportion of patients receive high VT and low PEEP levels. PPCs occur frequently in patients at increased risk, with worse clinical outcome

    Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications: LAS VEGAS - An observational study in 29 countries

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    BACKGROUND Limited information exists about the epidemiology and outcome of surgical patients at increased risk of postoperative pulmonary complications (PPCs), and how intraoperative ventilation was managed in these patients. OBJECTIVES To determine the incidence of surgical patients at increased risk of PPCs, and to compare the intraoperative ventilation management and postoperative outcomes with patients at low risk of PPCs. DESIGN This was a prospective international 1-week observational study using the ‘Assess Respiratory Risk in Surgical Patients in Catalonia risk score’ (ARISCAT score) for PPC for risk stratification. PATIENTS AND SETTING Adult patients requiring intraoperative ventilation during general anaesthesia for surgery in 146 hospitals across 29 countries. MAIN OUTCOME MEASURES The primary outcome was the incidence of patients at increased risk of PPCs based on the ARISCAT score. Secondary outcomes included intraoperative ventilatory management and clinical outcomes. RESULTS A total of 9864 patients fulfilled the inclusion criteria. The incidence of patients at increased risk was 28.4%. The most frequently chosen tidal volume (V T) size was 500 ml, or 7 to 9 ml kg−1 predicted body weight, slightly lower in patients at increased risk of PPCs. Levels of positive end-expiratory pressure (PEEP) were slightly higher in patients at increased risk of PPCs, with 14.3% receiving more than 5 cmH2O PEEP compared with 7.6% in patients at low risk of PPCs (P ˂ 0.001). Patients with a predicted preoperative increased risk of PPCs developed PPCs more frequently: 19 versus 7%, relative risk (RR) 3.16 (95% confidence interval 2.76 to 3.61), P ˂ 0.001) and had longer hospital stays. The only ventilatory factor associated with the occurrence of PPCs was the peak pressure. CONCLUSION The incidence of patients with a predicted increased risk of PPCs is high. A large proportion of patients receive high V T and low PEEP levels. PPCs occur frequently in patients at increased risk, with worse clinical outcome.</p
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