We have developed an SI-traceable narrow-band tunable radiance source based on an optical parametric oscillator (OPO) and an integrating sphere for the calibration of spectroradiometers. The source is calibrated with a reference detector over the ultraviolet/visible spectral range with an uncertainty of <1%. As a case study, a CubeSat spectroradiometer has been calibrated for radiance over its operating range from 370 nm to 480 nm. To validate the results, the instrument has also been calibrated with a traditional setup based on a diffuser and an FEL lamp. Both routes show good agreement within the combined measurement uncertainty. The OPO-based approach could be an interesting alternative to the traditional method, not only because of reduced measurement uncertainty, but also because it directly allows for wavelength calibration and characterization of the instrumental spectral response function and stray light effects, which could reduce calibration time and cost.
Background The caesarean delivery (CD) rate has risen in most countries over the last decades, but it remains relatively low in the Netherlands. Our objective was to analyse the trends of CD rates in various subgroups of women between 2000 and 2010, and identify the practice pattern that is attributable to the relative stability of the Dutch CD rate. Methods A total of 1,935,959 women from the nationwide Perinatal Registry of the Netherlands were included. Women were categorized into ten groups based on the modified CD classification scheme. Trends of CD rates in each group were described. Results The overall CD rate increased slightly from 14.0% in 2000–2001 to 16.7% in 2010. Fetal, early and late neonatal mortality rates decreased by 40–50% from 0.53%, 0.21%, 0.04% in 2000–2001 to 0.29%, 0.12%, 0.02% in 2010, respectively. During this period, the prevalence of non-vertex presentation decreased from 6.7% to 5.3%, even though the CD rate in this group was high. The nulliparous women with spontaneous onset of labor at term and a singleton child in vertex presentation had a CD rate of 9.9%, and 64.7% of multiparouswomen with at least one previous uterine scar and a singleton child in vertex presentation had a trial of labor and the success rate of vaginal delivery was 45.9%. Conclusions The Dutch experience indicates that external cephalic version for breech presentation, keeping the CD rate low in nulliparous women and encouraging a trial of labor in multiparous women with a previous scar, could help to keep the overall CD rate steady
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Meer bewegen vraagt meer energie. Het lijkt daarom logisch te veronderstellen dat wie beweegt daardoor ook meer gaat eten. Heeft het dan wel zin om meer te gaan bewegen om af te vallen. In dit artikel wordt een wiskundig model opgesteld. De "energiebalans" kan worden beschreven met een eerste orde lineaire differentiaalvergelijking. Oplossing van deze vergelijking laat zien dat het inderdaad zin heeft om meer te bewegen.
