Nieuwe grondhouding in ruimtelijk beleid

Op basis van een analyse van de veranderende ruimtelijke praktijk aan de hand van de ideeën van Williamson schetsen de auteurs van dit artikel twee handelingsperspectieven waarmee een nieuwe vorm van ruimtelijk beleid vorm kan krijgen. Twee handelingsperspectieven waarbij niet alleen het institutionele landschap, maar ook de planningscultuur en governance capaciteiten van ruimtelijke planners in beschouwing worden genomen. Het gaat om strategisch navigeren en lerend organiseren

First release of Apertif imaging survey data

Context. Apertif is a phased-array feed system for the Westerbork Synthesis Radio Telescope, providing forty instantaneous beams over 300 MHz of bandwidth. A dedicated survey program utilizing this upgrade started on 1 July 2019, with the last observations taken on 28 February 2022. The imaging survey component provides radio continuum, polarization, and spectral line data. Aims. Public release of data is critical for maximizing the legacy of a survey. Toward that end, we describe the release of data products from the first year of survey operations, through 30 June 2020. In particular, we focus on defining quality control metrics for the processed data products. Methods. The Apertif imaging pipeline, Apercal, automatically produces non-primary beam corrected continuum images, polarization images and cubes, and uncleaned spectral line and dirty beam cubes for each beam of an Apertif imaging observation. For this release, processed data products are considered on a beam-by-beam basis within an observation. We validate the continuum images by using metrics that identify deviations from Gaussian noise in the residual images. If the continuum image passes validation, we release all processed data products for a given beam. We apply further validation to the polarization and line data products and provide flags indicating the quality of those data products. Results. We release all raw observational data from the first year of survey observations, for a total of 221 observations of 160 independent target fields, covering approximately one thousand square degrees of sky. Images and cubes are released on a per beam basis, and 3374 beams (of 7640 considered) are released. The median noise in the continuum images is 41.4 uJy beam(-1), with a slightly lower median noise of 36.9 uJy beam(-1) in the Stokes V polarization image. The median angular resolution is 11.6 \u27\u27/sin delta. The median noise for all line cubes, with a spectral resolution of 36.6 kHz, is 1.6 mJy beam(-1), corresponding to a 3-sigma H i column density sensitivity of 1.8 x 10(20) atoms cm(-2) over 20 km s(-1) (for a median angular resolution of 24 \u27\u27 x 15 \u27\u27). Line cubes at lower frequency have slightly higher noise values, consistent with the global RFI environment and overall Apertif system performance. We also provide primary beam images for each individual Apertif compound beam. The data are made accessible using a Virtual Observatory interface and can be queried using a variety of standard tools

Effects of the element separation on the noise performance of receiving antenna arrays

Antenna arrays of closely separated elements can be used to achieve a large field of view of a radio telescope with highly efficient multiple beams. However, due to strong mutual coupling effects which exist in such dense arrays, the receiver noise can degrade. To reduce this noise degradation, the optimal noise match condition should be satisfied for all scan angles. This paper presents results of the noise performance analysis of small arrays of dipoles that were obtained for several element separation distances covering both conventional and dense arrays. The receiver noise temperatures are calculated for different noise match situations and the minimum noise temperature conditions are discussed

Student charettes: a magic toolbox

The research group of the Lectoraat Groene Leefomgeving van Steden has published this book to show that charrettes represent a highly interesting new component of the teaching programme at Van Hall Larenstein. They enable students to get a first taste of the professional setting they might end up working in, and teachers to tailor their teaching to professional practice. The charrettes also enable Van Hall Larenstein to enter into numerous new collaborations with Dutch and international partners, and it also uses the charrettes to show how interesting learning can be and – at least as importantly – how much fun. The teachers and organisers of the charrettes hope that this book may inspire the development of many new charrettes

Learning where to look: Electrophysiological and behavioral indices of visual search in young and old subjects.

Explored 24 young (aged 18-24 yrs) and 24 elderly (aged 65-75 yrs) right-handed males' use of regularities in target location in a visual display to guide searching for targets. Although both young and elderly Ss showed efficient use of search strategies, slight differences in reaction times suggest decreased ability in elderly Ss' use of complex cues. In young Ss, P3 amplitudes were larger for trials where the rule that governed the location of the target became evident. Enhanced slow wave (SW) amplitude indicated uncertainty in random search conditions. Elderly Ss' P3 and SW amplitudes, however, seemed unrelated to behavioral performance. Results suggest that age-related differences in search tasks can be understood in terms of age-related changes in strategies of allocating visual attention

Removal of ocular artifacts from the REM sleep EEG

The present report concerns the first study in which electrooculographic (EOG) contamination of electroencephalographic (EEG) recordings in rapid eye movement (REM) sleep is systematically investigated. Contamination of REM sleep EEG recordings in six subjects was evaluated in the frequency domain. REM-active and REM-quiet series were obtained for each subject. Transfer coefficients and power spectra of EOG and EEG indicated that (a) increases in transfer coefficients beyond 4.5 Hz are brought about by residual EEG in the EOG, and (b) EOG-EEG contamination in the delta band is most pronounced in frontal, intermediate in central and negligible in occipital leads. It was found that correction of the REM-active series resulted in significant (c) reductions in power, (d) increases in interhemispheric coherences and (e) reductions in degree of lateral asymmetry. These effects were largest for frontal leads, but still marked for central ones. The results are discussed in the light of previous findings concerning models of hemispheric functioning during REM sleep