Hechtingsrepresentaties en sensitiviteit: De modererende rol van posttraumatische stressstoornis bij een steekproef onder vluchtelingen

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Attachment representation and sensitivity: The moderating role of posttraumatic stress disorder in a refugee sample

It has been hypothesized that adult attachment representations guide caregiving behavior and influence parental sensitivity, and thus affect the child's socio-emotional development. Several studies have shown a link between posttraumatic stress disorder (PTSD) and reduced parental sensitivity, so it is possible that PTSD moderates the relationship between insecure attachment representations and insensitivity. In this study symptoms of PTSD (Harvard Trauma Questionnaire), parental sensitivity (Emotional Availability Scales), and attachment representations (Attachment Script Assessment) were assessed in 53 parents who were asylum seekers or refugees. Results showed that when parents were less able to draw on secure attachment representations, symptoms of PTSD increased the risk of insensitive parenting. These findings suggest that parental sensitivity is affected not just by attachment representations, but by a conjunction of risk factors including symptoms of PTSD and insecure attachment representations. These parents should therefore be supported to establish or confirm secure models of attachment experiences, to facilitate their ability interact sensitively and form a secure relationship with their children

Parental PTSD, adverse parenting and child attachment in a refugee sample

Item does not contain fulltextIn contrast with traumatic experiences, there is a dearth of studies on the link between trauma symptoms, disconnected (frightened, threatening and dissociative) parenting behavior, extremely insensitive parenting behavior and child attachment. This study extends previous work on the impact of posttraumatic stress disorder (PTSD) on families by studying the unique contribution of disconnected and extremely insensitive parenting behavior on child attachment in a highly traumatized sample of 68 asylum seekers and refugees and their children (18-42 months). The results show that parental symptoms of PTSD are directly related to children's insecure attachment and disorganized attachment. The greatest proportion of the risk could be attributed to factors related to the dyad and not the family. A mediation effect of adverse parenting behavior was not confirmed. On the one hand the results indicate the need for an effective treatment of PTSD symptomatology while on the other hand the results indicate the need for clinical attention to insecure attachment relationships.19 p

Highly porous, ultra-low refractive index coatings produced throughrandom packing of silicated cellulose nanocrystals

The use of cellulose nanocrystals (CNCs) in optical materials has been extensively studied. Key in mostapplications reported to date is the chiral nematic ordering of CNCs. Here, we demonstrate that randompacking of silicated CNCs can also yield materials with interesting optical properties, i.e., highly porous,ultra-low refractive index coatings. Needle-shaped CNCs with an aspect ratio of 25 were extracted fromAvicel, and subsequently covered with a silica layer. In one single dip coating step, highly porous coatingsof CNC-silica core–shell particles were deposited on glass slides and silicon wafers. The lowest refractiveindex achieved was 1.03, which corresponds to a porosity of 94%; the thickness of these coatings rangedfrom 101 nm to 239 nm. The substrates, coated with a layer of CNC-silica core–shell particles, were heatedto 450◦C for two hours. Cellulose was removed through pyrolysis, which resulted in porous coatingsof sub-micron sized hollow silica rods. The porosity increase generated through pyrolysis of cellulose,however, was largely compensated by the decrease in packing porosity due to shrinkage of the coating

Development of photonic crystal structures for on-board optical communication

We present designs for sharp bends in polymer waveguides using colloidal photonic crystal (PhC) structures. Both silica (SiO2) sphere based colloidal PhC and core-shell colloidal PhC structures having a titania (TiO 2) core inside silica (SiO2) shells are simulated. The simulation results show that core-shell Face Centered Cubic (FCC) colloidal crystals have a sufficient refractive index contrast to open up a bandgap in the desired direction when integrated into polymer waveguides and can achieve reflection >70% for the appropriate plane. Different crystal planes of the FCC structure are investigated for their reflection and compared with the calculated bandstructure. Different techniques for fabrication of PhC on rectangular seed layers namely slow sedimentation; spin coating and modified doctor blading are discussed and investigated. FCC and Random FCC silica structures are characterized optically to show realisation of (001) FCC. © 2014 SPIE

Detection of low concentration formaldehyde gas by photonic crystal sensor fabricated by nanoimprint process in polymer material

This paper describes experimental measurement results for photonic crystal sensor devices which have been functionalized for gas sensing applications. The sensor consists of a two dimensional photonic crystal etched into a slab waveguide having a refractive index of 1.7-1.9. Test devices were fabricated from SiON material on silicon/ silicon dioxide platform, and also in polymer materials on silicon platform. The inorganic photonic crystals were made using direct write electron-beam lithography and reactive ion etching. The polymeric devices were made by nano-imprint lithography using the SiON structure as the imprint master. The high refractive index polymer was composed of a TiO 2- UV resin nanocomposite having a nanoparticle fraction between 50 and 60 wt%. This resulted in a tunable refractive index between 1.7 and 1.85. Devices were functionalized for gas sensing applications by coating the surface with a chemical receptor. This responsive layer reacts with the target gas and changes its refractive index. This change causes the angle of out-coupling to change slightly. In this paper we report successful detection of formaldehyde in air at sub ppm levels, and discuss details of chemical functionalization of the PC sensor. cop. 2014 SPIE

Reactor effluent verwerking met behulp van absorber en destillatiekolom

Document uit de collectie Chemische ProcestechnologieDelftChemTechApplied Science

Electroweak measurements in electron–positron collisions at w-boson-pair energies at lep

Contains fulltext : 121524.pdf (preprint version ) (Open Access