University of Amsterdam

About: University of Amsterdam is a education organization based out in Amsterdam, Noord-Holland, Netherlands. It is known for research contribution in the topics: Population & Context (language use). The organization has 59309 authors who have published 140894 publications receiving 5984137 citations. The organization is also known as: UvA & Universiteit van Amsterdam.

In vitro fertilization with preimplantation genetic screening.

Abstract: BACKGROUND Pregnancy rates in women of advanced maternal age undergoing in vitro fertilization (IVF) are disappointingly low. It has been suggested that the use of preimplantation genetic screening of cleavage-stage embryos for aneuploidies may improve the ef- fectiveness of IVF in these women. METHODS We conducted a multicenter, randomized, double-blind, controlled trial comparing three cycles of IVF with and without preimplantation genetic screening in women 35 through 41 years of age. The primary outcome measure was ongoing pregnancy at 12 weeks of gestation. The secondary outcome measures were biochemical preg- nancy, clinical pregnancy, miscarriage, and live birth. RESULTS Four hundred eight women (206 assigned to preimplantation genetic screening and 202 assigned to the control group) underwent 836 cycles of IVF (434 cycles with and 402 cycles without preimplantation genetic screening). The ongoing-pregnancy rate was significantly lower in the women assigned to preimplantation genetic screen- ing (52 of 206 women (25%)) than in those not assigned to preimplantation genetic screening (74 of 202 women (37%); rate ratio, 0.69; 95% confidence interval (CI), 0.51 to 0.93). The women assigned to preimplantation genetic screening also had a significantly lower live-birth rate (49 of 206 women (24%) vs. 71 of 202 women (35%); rate ratio, 0.68; 95% CI, 0.50 to 0.92). CONCLUSIONS Preimplantation genetic screening did not increase but instead significantly reduced the rates of ongoing pregnancies and live births after IVF in women of advanced maternal age. (Current Controlled Trials number, ISRCTN76355836.)

The sixth visual object tracking VOT2018 challenge results

Abstract: The Visual Object Tracking challenge VOT2018 is the sixth annual tracker benchmarking activity organized by the VOT initiative. Results of over eighty trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in the recent years. The evaluation included the standard VOT and other popular methodologies for short-term tracking analysis and a “real-time” experiment simulating a situation where a tracker processes images as if provided by a continuously running sensor. A long-term tracking subchallenge has been introduced to the set of standard VOT sub-challenges. The new subchallenge focuses on long-term tracking properties, namely coping with target disappearance and reappearance. A new dataset has been compiled and a performance evaluation methodology that focuses on long-term tracking capabilities has been adopted. The VOT toolkit has been updated to support both standard short-term and the new long-term tracking subchallenges. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The dataset, the evaluation kit and the results are publicly available at the challenge website (http://votchallenge.net).

Active galactic nuclei as scaled-up Galactic black holes

Abstract: The central engines that drive active galactic nuclei are thought to be supermassive black holes. A long-standing question in astrophysics is whether these central engines vary like Galactic black hole systems when scaled up to 'supermassive' proportions. If they do, it becomes possible to predict how active galactic nuclei should behave on cosmological timescales by studying the brighter and much faster varying Galactic systems. A new study suggests that yes, the accretion process is exactly the same for small and large black holes. Provided, that is, that a correction is made to take account of variations in the rate of the accretion process. Active galactic nuclei vary in a manner similar to Galactic black hole systems when appropriately scaled up by mass, meaning it is possible to determine how active galactic nuclei should behave on cosmological timescales by studying the brighter and much faster varying Galactic systems. A long-standing question is whether active galactic nuclei (AGN) vary like Galactic black hole systems when appropriately scaled up by mass1,2,3. If so, we can then determine how AGN should behave on cosmological timescales by studying the brighter and much faster varying Galactic systems. As X-ray emission is produced very close to the black holes, it provides one of the best diagnostics of their behaviour. A characteristic timescale—which potentially could tell us about the mass of the black hole—is found in the X-ray variations from both AGN and Galactic black holes1,2,3,4,5,6, but whether it is physically meaningful to compare the two has been questioned7. Here we report that, after correcting for variations in the accretion rate, the timescales can be physically linked, revealing that the accretion process is exactly the same for small and large black holes. Strong support for this linkage comes, perhaps surprisingly, from the permitted optical emission lines in AGN whose widths (in both broad-line AGN and narrow-emission-line Seyfert 1 galaxies) correlate strongly with the characteristic X-ray timescale, exactly as expected from the AGN black hole masses and accretion rates. So AGN really are just scaled-up Galactic black holes.