156 research outputs found

    Records of five bryozoan species from offshore gas platforms rare for the Dutch North Sea

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    This study reports on bryozoan species collected at three offshore gas platforms in the Dutch part of the North Sea. Four out of thirteen observed species are considered as rare in the Netherlands, whereas Cribrilina punctata is anew species for Dutch waters

    Broadband Optical Serrodyne Frequency Shifting

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    We demonstrate serrodyne frequency shifting of light from 200 MHz to 1.2 GHz with an efficiency of better than 60 percent. The frequency shift is imparted by an electro-optic phase modulator driven by a high-frequency, high-fidelity sawtooth waveform that is passively generated by a commercially available Non-Linear Transmission Line (NLTL). We also implement a push-pull configuration using two serrodyne-driven phase modulators allowing for continuous tuning between -1.6 GHz and +1.6 GHz. Compared to competing technologies, this technique is simple and robust, and offers the largest available tuning range in this frequency band.Comment: 3 pages, 4 figure

    Comparison of the finite volume and discontinuous Galerkin schemes for the double vortex pairing problem using the SU2 software suite

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    A numerical investigation of finite volume (FV) and discontinuous Galerkin (DG) finite element methods in the framework of the SU2 software is presented. The accuracy of different numerical variants is assessed with reference to the low Mach double vortex pairing flow problem, which has recently been proposed as a benchmark for studying the properties of structured and unstructured grid based methods with respect to turbulent-like vortices. The present study reveals that low-Mach corrections significantly improve the accuracy of second- and third-order, unstructured grid based schemes, at flow speeds in the incompressible limit. Furthermore, the 3rd-order DG method produces results similar to 11th-order accurate FV volume schemes

    Duurzame maĂŻsteelt op zandgrond : verslag van een deskundigendag, gehouden op 22 april 2010

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    Voor de melkveehouderij op zandgrond is de maïsteelt belangrijk. Zetmeelrijke, eiwitarme maïs combineert uitstekend met zetmeelarm maar eiwitrijk gras, wat goed is voor de koe maar ook voor het milieu omdat een maïsgewas zeer efficiënt met water omgaat en omdat een rantsoen met maïs de emissies van lachgas en ammoniak beperkt. Bovendien kan door de voeding van maïs op krachtvoer worden bespaard. Daar staat tegenover dat op veel bedrijven bij de maïsteelt te veel meststoffen en herbiciden naar het grond- en oppervlaktewater verloren gaan. Dat maakt het voor waterbeheerders moeilijk te voldoen aan de kwaliteitsnormen die de Kaderrichtlijn Water (KRW) stelt. Ook de maïstelers zijn daar niet blij mee, omdat dit duidt op een slechte benutting van grondstoffen. De teeltkosten zijn dan te hoog, de gewasopbrengsten te laag, of de bodemkwaliteit lijdt eronder

    Two Decades of Research on Euthanasia from the Netherlands. What Have We Learnt and What Questions Remain?

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    Two decades of research on euthanasia in the Netherlands have resulted into clear insights in the frequency and characteristics of euthanasia and other medical end-of-life decisions in the Netherlands. These empirical studies have contributed to the quality of the public debate, and to the regulating and public control of euthanasia and physician-assisted suicide. No slippery slope seems to have occurred. Physicians seem to adhere to the criteria for due care in the large majority of cases. Further, it has been shown that the majority of physicians think that the euthanasia Act has improved their legal certainty and contributes to the carefulness of life-terminating acts. In 2005, eighty percent of the euthanasia cases were reported to the review committees. Thus, the transparency envisaged by the Act still does not extend to all cases. Unreported cases almost all involve the use of opioids, and are not considered to be euthanasia by physicians. More education and debate is needed to disentangle in these situations which acts should be regarded as euthanasia and which should not. Medical end-of-life decision-making is a crucial part of end-of-life care. It should therefore be given continuous attention in health care policy and medical training. Systematic periodic research is crucial for enhancing our understanding of end-of-life care in modern medicine, in which the pursuit of a good quality of dying is nowadays widely recognized as an important goal, in addition to the traditional goals such as curing diseases and prolonging life

    Coulomb Blockade in a Silicon/Silicon-Germanium Two-Dimensional Electron Gas Quantum Dot

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    We report the fabrication and electrical characterization of a single electron transistor in a modulation doped silicon/silicon-germanium heterostructure. The quantum dot is fabricated by electron beam lithography and subsequent reactive ion etching. The dot potential and electron density are modified by laterally defined side gates in the plane of the dot. Low temperature measurements show Coulomb blockade with a single electron charging energy of 3.2 meV.Comment: Typos corrected; to appear in Appl. Phys. Let

    Cervical pessary versus vaginal progesterone in women with a singleton pregnancy, a short cervix, and no history of spontaneous preterm birth at less than 34 weeks’ gestation: open label, multicentre, randomised, controlled trial

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    OBJECTIVE To compare the effectiveness of cervical pessary and vaginal progesterone in the prevention of adverse perinatal outcomes and preterm birth in pregnant women of singletons with no prior spontaneous preterm birth at less than 34 weeks’ gestation and who have a short cervix of 35 mm or less. DESIGN Open label, multicentre, randomised, controlled trial. SETTING 20 hospitals and five obstetric ultrasound practices in the Netherlands. PARTICIPANTS Women with a healthy singleton pregnancy and an asymptomatic short cervix of 35 mm or less between 18 and 22 weeks’ gestation were eligible. Exclusion criteria were prior spontaneous preterm birth at less than 34 weeks, a cerclage in situ, maternal age of younger than 18 years, major congenital abnormalities, prior participation in this trial, vaginal blood loss, contractions, cervical length of less than 2 mm or cervical dilatation of 3 cm or more. Sample size was set at 628 participants. INTERVENTIONS 1:1 randomisation to an Arabin cervical pessary or vaginal progesterone 200 mg daily up to 36 weeks’ of gestation or earlier in case of ruptured membranes, signs of infection, or preterm labour besides routine obstetric care. MAIN OUTCOME MEASURES Primary outcome was a composite adverse perinatal outcome. Secondary outcomes were rates of (spontaneous) preterm birth at less than 28, 32, 34, and 37 weeks. A predefined subgroup analysis was planned for cervical length of 25 mm or less. RESULTS From 1 July 2014 to 31 March 2022, 635 participants were randomly assigned to pessary (n=315) or to progesterone (n=320). 612 were included in the intention to treat analysis. The composite adverse perinatal outcome occurred in 19 (6%) of 303 participants with a pessary versus 17 (6%) of 309 in the progesterone group (crude relative risk 1.1 (95% confidence interval (CI) 0.60 to 2.2)). The rates of spontaneous preterm birth were not significantly different between groups. In the subgroup of cervical length of 25 mm or less, spontaneous preterm birth at less than 28 weeks occurred more often after pessary than after progesterone (10/62 (16%) v 3/69 (4%), relative risk 3.7 (95% CI 1.1 to 12.9)) and adverse perinatal outcomes seemed more frequent in the pessary group (15/62 (24%) v 8/69 (12%), relative risk 2.1 (0.95 to 4.6)). CONCLUSIONS In women with a singleton pregnancy with no prior spontaneous preterm birth at less than 34 weeks’ gestation and with a midtrimester short cervix of 35 mm or less, pessary is not better than vaginal progesterone. In the subgroup of a cervical length of 25 mm or less, a pessary seemed less effective in preventing adverse outcomes. Overall, for women with single baby pregnancies, a short cervix, and no prior spontaneous preterm birth less than 34 weeks’ gestation, superiority of a cervical pessary compared with vaginal progesterone to prevent preterm birth and consecutive adverse outcomes could not be proven
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