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Context. Optical interferometry is at a key development stage. The Very Large Telescope Interferometer (VLTI) has established a stable, robust infrastructure for long-baseline interferometry that is usable by general astronomical observers. The present second-generation instruments offer a wide wavelength coverage and improved performance. Their sensitivity and measurement accuracy lead to data and images of high reliability. Aims. We have developed the Multi AperTure mid-Infrared SpectroScopic Experiment (MATISSE) to access, for the first time, high resolution imaging in a wide spectral domain. Many front-line topics are explored with this new equipment, including: stellar activity and mass loss; planet formation and evolution in the gas and dust disks around young stars; and environment interaction and accretion processes around super massive black holes in active galactic nuclei. Methods. The instrument is a spectro-interferometric imager in the transmission windows called L, M, and N, from 2.8 to 13.0 microns, combining four optical beams from the VLTI's unit or auxiliary telescopes. Its concept, related observing procedure, data reduction, and calibration approach, is the product of 30 years of instrumental research and has benefitted from the expertise developed in the frame of the VLTI's first generation instruments. The instrument utilises a multi-axial beam combination that delivers spectrally dispersed fringes. The signal provides the following quantities at several spectral resolutions: photometric flux, coherent fluxes, visibilities, closure phases, wavelength differential visibilities and phases, and aperture-synthesis imaging. Results. This article provides an overview of the physical principle of the instrument and its functionalities. The motivation of the choice of the instrumental concept and the characteristics of the delivered signal are detailed with a description of the observing modes and of their performance limit. MATISSE offers four spectra

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Contains fulltext : 235950.pdf (Publisher’s version ) (Open Access)

Context. A complex environment exists in the inner few astronomical units of planet-forming disks. High-angular-resolution observations play a key role in our understanding of the disk structure and the dynamical processes at work.Aims. In this study we aim to characterize the mid-infrared brightness distribution of the inner disk of the young intermediate-mass star HD 163296 from early VLTI/MATISSE observations taken in the L- and N-bands. We put special emphasis on the detection of potential disk asymmetries.Methods. We use simple geometric models to fit the interferometric visibilities and closure phases. Our models include a smoothed ring, a flat disk with an inner cavity, and a 2D Gaussian. The models can account for disk inclination and for azimuthal asymmetries as well. We also perform numerical hydrodynamical simulations of the inner edge of the disk.Results. Our modeling reveals a significant brightness asymmetry in the L-band disk emission. The brightness maximum of the asymmetry is located at the NW part of the disk image, nearly at the position angle of the semimajor axis. The surface brightness ratio in the azimuthal variation is 3.5 +/- 0.2. Comparing our result on the location of the asymmetry with other interferometric measurements, we confirm that the morphology of the r < 0.3 au disk region is time-variable. We propose that this asymmetric structure, located in or near the inner rim of the dusty disk, orbits the star. To find the physical origin of the asymmetry, we tested a hypothesis where a vortex is created by Rossby wave instability, and we find that a unique large-scale vortex may be compatible with our data. The half-light radius of the L-band-emitting region is 0.33 +/- 0.01 au, the inclination is 52 degrees(+5 degrees)(-7 degrees) 52 degrees-7 degrees+5 degrees , and the position angle is 143 degrees +/- 3 degrees. Our models predict that a non-negligible fraction of the L-band disk emission originates inside the dust sublimation radius fo

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Contains fulltext : 126866.pdf (publisher's version ) (Closed access), The work of group care workers in residential youth care is often described as professional parenting. Pedagogical interventions of group care workers influence the quality of care for looked-after children. The aim of the current study was to observe the pedagogical interventions of group care workers within residential youth care and their associations with child behaviors. Group care worker interventions and child behaviors were videotaped during structured observations. Participants included 95 children (64 % boys, M (age) = 9.19) and 53 group care workers (74 % female, M (age) = 33.79 years). A coding system was developed to code pedagogical interventions and child behaviors. It showed that group care workers mainly used positive pedagogical interventions (warmth/support and positive control) and seldom used negative pedagogical interventions (permissiveness and negative control). Frustration and anger of children was associated with positive controlling interventions and permissiveness of group care workers. The hypothesis that child anxiety and nervousness is associated with warm and supportive interventions could not be confirmed. Pedagogical interventions should be part of education, training, and supervision of group care workers.

Radboud Universiteit Nijmegen, 22 mei 2014, Promotores : Veerman, J.W., Engels, R.C.M.E. Co-promotor : Kroes, G., Contains fulltext : 127102.pdf (publisher's version ) (Open Access)

Item does not contain fulltext, Iedere ouder ervaart bij tijd en wijle weleens stress bij het opvoeden. Wanneer deze stress niet van tijdelijke aard is of wanneer de stress erg hoog wordt, kan professionele hulp ingeschakeld worden. Het vaststellen van de aard en ernst van de opvoedingsstress is dan van belang. De Opvoedingsbelastingvragenlijst (OBVL) is een recent ontwikkeld instrument hiervoor. De uitkomsten van het hier beschreven onderzoek geven positieve aanwijzingen voor de betrouwbaarheid en validiteit van de OBVL. De OBVL is ontwikkeld voor instellingen voor jeugdzorg, maar is ook op andere terreinen van zorg voor kinderen goed bruikbaar. De lijst is geschikt voor screening, diagnostiek en evaluatie van behandelingen.

Item does not contain fulltext, Group care workers in residential youth care are considered important in influencing behavioral development of children. In spite of this, their role has largely been neglected in research on residential care. The aim of the current study was twofold. First, longitudinal changes in group care worker interventions and child behaviors were investigated separately. Second, bidirectional influences between group care worker interventions and child behaviors were investigated. Group care workers completed the Group care worker Intervention Checklist and Child Behavior Checklist for 128 children (66% boys, mean age 8.63 years) at the beginning of the treatment and at two measurement intervals that followed (6 and 12 months, respectively). Most results contradicted the predictions. There was no change in controlling and warm and supportive interventions by group care workers. Autonomy granting interventions increased during treatment. Second, there were no changes in externalizing and internalizing behaviors of children over time.Third, cross-lagged analyses revealed that higher levels of controlling interventions increased externalizing problems of children. In the opposite direction, higher levels of children's externalizing problems were associated with an increase in controlling interventions of group care workers. In addition, higher levels of children's internalizing problems were associated with lower subsequent levels of autonomy granting interventions. These significant longitudinal paths were found only for the first phase of treatment. This study emphasizes the potential of the role of group care workers in residential youth care. Residential institutions should be aware of the dynamics between group care workers and children. Training and ongoing supervision in effective responses to behavior problems can increase the effect of group care worker interventions on child behavioral changes.

Contains fulltext : 102692.pdf (publisher's version ) (Closed access), Background By interacting with children, group care workers shape daily living environments to influence treatment. Current literature provides little knowledge about the content of youth residential care. Objective In this study, a questionnaire called the Group care worker Intervention Checklist was developed. Method Group care workers completed the questionnaires for 212 children placed in youth residential care in the Netherlands. Results Factor analyses revealed three constructs: controlling, warmth/support, and autonomy granting. Reliability of these scales proved to be good. Controlling was associated with Externalizing Behavior Problems while both Warmth/Support and Autonomy Granting were associated with Internalizing Behavior Problems. Conclusions These findings imply that group care worker interventions can be reliably measured and are related to child problem behavior.

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A new predictive computational method for classifying clathrate hydrate promoter molecules is presented, based on the interaction energies between potential promoters and the water networks of sII and sH clathrates. The motivation for this work is identifying promoters for storing hydrogen compactly in clathrate hydrates. As a first step towards achieving this goal, we have developed a general method aimed at distinguishing between molecules that form sII clathrate hydrates and molecules that can - together with a weakly interacting help gas - form sH clathrate hydrates. The new computational method calculates differences in estimated formation energies of the sII and the sH clathrate hydrate. Model interaction potentials have been used, including the electrostatic interactions with newly calculated partial charges for all the considered potential promoter molecules. The methodology can discriminate between the clathrate structure types (sII or sH) formed by each potential promoter with good selectivity, i.e., better than achieved with a simple van der Waals diameter criterion.

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Contains fulltext : 90608.pdf (publisher's version ) (Closed access), The role of acquaintanceship with the child on reports of child behaviour by different informants was examined within the framework of a general theory of personality judgment. Mothers of referred children and group-care workers rated videotaped behaviour samples of a well known and an unknown child in the clinic. Independent observers also rated the videotapes. In line with the acquaintanceship hypothesis, mothers were found to perceive more behaviour problems than independent observers when rating well known children but not unknown children. Contrary to the acquaintanceship hypothesis, however, the group-care workers in our study reported more behaviour problems than the other informants regardless of their acquaintance with the children. The clinical and methodological implications of these findings are discussed.