First-Principles Theoretical Studies of Bulk, Defect and Interface properties of Oxide Semiconductors

Oxide semiconductors have been shown to exhibit rich physics related to their bulk, defect and interface properties. First-principles calculations have and will continue to play a major role in developing an understanding of the microscopic origins of these phenomena. In this thesis, first-principles studies are presented for several oxide semiconductors, with a view to understand how their microscopic properties ultimately determine device functionality. In Chapter 3, a detailed study of bulk SrZrO3 and Sr(Ti,Zr)O3 alloys is performed. For Sr(Ti,Zr)O3 alloys with 50% Ti concentration, we find that arranging the Ti and Zr atoms into a 1×1 SrZrO3/SrTiO3 superlattice along the [001] direction leads to breaking of the conduction band t2g orbital degeneracy, which could suppress scattering due to electron-phonon interactions. In Chapter 4, we present an investigation into the properties of native defects and hydrogen in SrZrO3. It is found that oxygen and strontium vacancies are the dominant defects in the absence of impurity doping, and will form deep donor and deep acceptor states, respectively. Hydrogen is found to be amphoteric in this material at different lattice sites; additionally, this impurity forms a stable complex with oxygen vacancies. In Chapter 5, the tendency for ABO3 perovskite oxides with 3dn B-cations to exhibit ferroelectricity and multiferroicity is investigated. Using the LaBO3 series as a model, we find that initially, as electrons are added to the B-cation d orbital, the tendency for the system to exhibit a ferroelectric distortion disappears - however, for high spin d5 - d7 and d8 cations a strong ferroelectric instability is recovered, and this effect is explained within the pseudo Jahn-Teller theory for ferroelectricity. This finding provides a new route for the design of strongly coupled magnetoelectric materials. In Chapters 6 and 7 the fundamental properties of the technologically important oxide heterostructure systems ZnO/MgZnO and SrTiO3/LaAlO3 are characterized. For the latter, we identify a previously unreported mechanism for interface induced magnetism based on surface aluminium vacancies, which will aid in interpreting experimental results for this system and other polar/non-polar oxide heterostructures

The question of symptom lateralization in conversion disorder

FSW - Self-regulation models for health behavior and Psychopathology - Ou

The question of symptom lateralization in conversion disorder

FSW - Self-regulation models for health behavior and Psychopathology - Ou

Mensen met een roeping: Een zegen of een zorg in de hulpverlening?

Contains fulltext : 143442.pdf (publisher's version ) (Open Access)Mensen met een roeping ervaren hun werk als zinvol. Roeping leidt tot een verhoogde motivatie voor het werk en zou daardoor met minder emotionele uitputting kunnen samenhangen. Ook het gerelateerde begrip spiritualiteit zou negatief samenhangen met emotionele uitputting. Roeping zou ook de relatie tussen emotionele belasting en uitputting kunnen modereren. Bij 235 medewerkers in de geestelijke gezondheidszorg werd dit onderzocht. Spiritualiteit overlapte slechts in geringe mate met roeping. Verder bleek er een positieve samenhang te zijn tussen emotionele belasting en emotionele uitputting en een negatieve samenhang tussen roeping en emotionele uitputting. Roeping verklaarde vier procent van de variantie in emotionele uitputting, maar modereerde de relatie tussen emotionele belasting en emotionele uitputting niet. Eén aspect van spiritualiteit, verbondenheid met ‘het zelf’, hing ook negatief samen met emotionele uitputting. Mensen met een roeping zijn dus niet op een speciale manier beschermd tegen emotionele belasting, maar hebben wel minder last van emotionele uitputting.18 p

Emotieregulatie en burnout bij ziekenverzorgenden

Contains fulltext : 73117.pdf ( ) (Open Access)This study analysed whether, amongst health care providers in a nursing homes setting, there is a relationship between, on the hand, work demands, autonomy, lack of social support and emotional labor; and on the other hand, symptoms of burnout. It also analysed whether the concept of emotional labor was an additional factor that helped explain variance in burnout over and above the concepts found in the Demand-Control-Support model. The study was based on 130 health care providers (response rate of 75%). Participants filled in a questionnaire that measured the Demand-Control-Support concepts of autonomy, lack of social support and work demands, as well as four dimensions of emotional labor. It assessed burnout in three dimensions, namely emotional exhaustion, depersonalisation and personal accomplishment. The results showed a relationship between work demands, social support, several aspects of emotional labor and burnout, whereas no relationship was found between autonomy and burnout. The various concepts, taken together, explained 28 to 30% of the variance in burnout. Emotional labor appeared to be a distinct additional factor in relation to burnout, supplementing the elements found in the Demand-Control-Support model. These results confirm the findings from previous studies in other professions. They demonstrate that, in professions involving a lot of contact with patients, emotional labor may represent a potentially important factor related to health.13 p

Somatoform dissociation and traumatic experiences in patients with rheumatoid arthritis and fibromyalgia

Contains fulltext : 52052.pdf ( ) (Open Access)OBJECTIVE: Trauma and dissociation tend to be interrelated. The objective of this study was to examine the frequency of traumatic experiences and somatoform dissociation in patients with fibromyalgia syndrome (FMS) or rheumatoid arthritis (RA), two conditions that are both characterized by pain and disability. METHODS: Patients with a diagnosis of FMS (2 male, 26 female; mean age 42 +/- 11 years) or RA (5 male, 46 female; mean age 46 +/- 10 years) completed the Fibromyalgia Impact Questionnaire (FIQ), the Somatoform Dissociation Questionnaire (SDQ), and the Traumatic Experience Checklist (TEC). RESULTS: Patients with FMS reported significantly higher levels of various forms of traumatization and dissociation than patients with RA. In patients with FMS, but not in patients with RA, there was a significant correlation between traumatization and dissociative symptoms. A possible dissociative disorder was indicated in 10% of the patients with FMS and 2% of the patients with RA. CONCLUSION: Traumatization experiences are frequent in FMS, but as compared to conversion disorder or dissociative identity disorder only a small subgroup of patients with FMS or RA shows the combination of traumatization and somatoform dissociation. The observation of somatoform dissociation calls for a broad treatment approach with a special role of the psychologist or psychiatrist.6 p

Dutch norms for the Rasch version of the Stanford Hypnotic Susceptibility Scale, Form C

The psychometric structure of the Stanford Hypnotic Susceptibility Scale, Form C was recently tested in a Rasch analysis. After omission of two items the scale fulfi lls the requirements of the Rasch model. The Rasch model justifi es the use of a sum score as a measure for a one-dimensional latent trait. It is argued that the new version enables a more reliable measurement of hypnotic susceptibility. In this study Dutch norms for the Rasch version of the SHSS-C Form C are presented