Ontwikkelingsprincipes voor de Inrichting van de Informatievoorziening over de Curatieve zorg

Political Scienc

High Resolution Imaging and the Formation of Stars and Planets

Understanding the formation of stellar and planetary systems is one of the great challenges of contemporary astrophysics. This thesis describes progress towards understanding these processes, through advancement of techniques to enable high resolution imaging of faint companions and other structures in the immediate environs of young stars. To ensure optimal performance in an era of large segmented telescopes, techniques to precisely cophase the mirror segments are required. In this thesis we propose the Fizeau Interferometric Cophasing of Segmented Mirrors algorithm, and present the results of testing both numerically and through experiment. We help to rectify a lack of observational evidence with which to test brown dwarf evolutionary models, by laying the foundation for an orbital monitoring survey of 19 brown dwarf binary systems and reporting the discovery of an additional 7 low mass companions to intermediate mass stars. We perform a Non-Redundant Masking (NRM) survey targeting the 1\,Myr old Ophiuchus star forming region. Both binary statistics and the relationship between multiplicity and the presence of a circumstellar disk are explored, providing many results similar to those from older regions. This helps frame the time evolution of effects related to dynamical interactions in binary systems, and the timescale of disk dissipation, with profound implications for giant planet formation. In thesis we also present the results of commissioning for the Gemini Planet Imager Non-Redundant Masking mode. These results indicate that the addition of an Extreme Adaptive Optics systems has substantially improved the performance of NRM compared to previous instruments. Finally, the transition disk T Cha is studied with multi-epoch NRM data, showing that the signal previously interpreted as a planetary companion is more likely to be the result of forward scattering from the inclined outer disk

Het hart van de geneeskunde

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Medical informatics in the heart of health care

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Clinical Problem analysis (CPA): A systematic approach to teaching complex medical problem solving

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