Omgaan met digitale nationale beleidskaarten

In dit werkdocument worden de resultaten besproken van een casestudy die onderdeel is van het project GeO3 - Omgaan met onzekerheid binnen Ruimtelijke Ordening. De directie Platteland van het ministerie van LNV heeft bij het publiceren van het meerjarenprogramma van Agenda Vitaal Platteland geen digitale viewer gepubliceerd omdat men bang was voor verkeerde interpretatie van de digitale kaarten. In dit project is gekeken naar methoden en cartografische oplossingen om voortaan zonder angst voor misinterpretaties digitale nationale beleidskaarten te kunnen verspreiden. De oplossing is gezocht in het opstellen van een handreiking, zodat kaarten ook daadwerkelijk weergeven wat er bedoeld is door de maker

Cochlear-optimized treatment planning in photon and proton radiosurgery for vestibular schwannoma patients

Objective: To investigate the potential to reduce the cochlear dose with robotic photon radiosurgery or intensity-modulated proton therapy planning for vestibular schwannomas. Materials and Methods: Clinically delivered photon radiosurgery treatment plans were compared to five cochlear-optimized plans: one photon and four proton plans (total of 120). A 1x12 Gy dose was prescribed. Photon plans were generated with Precision (Cyberknife, Accuray) with no PTV margin for set-up errors. Proton plans were generated using an in-house automated multi-criterial planning system with three or nine-beam arrangements, and applying 0 or 3 mm robustness for set-up errors during plan optimization and evaluation (and 3 % range robustness). The sample size was calculated based on a reduction of cochlear Dmean &gt; 1.5 Gy(RBE) from the clinical plans, and resulted in 24 patients. Results: Compared to the clinical photon plans, a reduction of cochlear Dmean &gt; 1.5 Gy(RBE) could be achieved in 11/24 cochlear-optimized photon plans, 4/24 and 6/24 cochlear-optimized proton plans without set-up robustness for three and nine-beam arrangement, respectively, and in 0/24 proton plans with set-up robustness. The cochlea could best be spared in cases with a distance between tumor and cochlea. Using nine proton beams resulted in a reduced dose to most organs at risk. Conclusion: Cochlear dose reduction is possible in vestibular schwannoma radiosurgery while maintaining tumor coverage, especially when the tumor is not adjacent to the cochlea. With current set-up robustness, proton therapy is capable of providing lower dose to organs at risk located distant to the tumor, but not for organs adjacent to it. Consequently, photon plans provided better cochlear sparing than proton plans.</p

The Gaia Ultra-Cool Dwarf Sample - III: Seven new multiple systems containing at least one Gaia DR2 ultracool dwarf.

We present 10 new ultracool dwarfs in seven wide binary systems discovered using Gaia second data release data, identified as part of our Gaia Ultra-Cool Dwarf Sample project. The seven systems presented here include an L1 companion to the G5 IV star HD 164507, an L1: Companion to the V478 Lyr AB system, an L2 companion to the metal-poor K5 V star CD-28 8692, an M9 V companion to the young variable K0 V star LT UMa, and three low-mass binaries consisting of late Ms and early Ls. The HD 164507, CD-28 8692, V478 Lyr, and LT UMa systems are particularly important benchmarks, because the primaries are well characterized and offer excellent constraints on the atmospheric parameters and ages of the companions. We find that the M8 V star 2MASS J23253550+4608163 is ∼2.5 mag overluminous compared to M dwarfs of similar spectral type, but at the same time it does not exhibit obvious peculiarities in its near-infrared spectrum. Its overluminosity cannot be explained by unresolved binarity alone. Finally, we present an L1+L2 system with a projected physical separation of 959 au, making this the widest L + L binary currently known.With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737