Generalized Conformal Symmetry in D-Brane Matrix Models

We study in detail the extension of the generalized conformal symmetry proposed previously for D-particles to the case of supersymmetric Yang-Mills matrix models of Dp-branes for arbitrary p. It is demonstrated that such a symmetry indeed exists both in the Yang-Mills theory and in the corresponding supergravity backgrounds produced by Dp-branes. On the Yang-Mills side, we derive the field-dependent special conformal transformations for the collective coordinates of Dp-branes in the one-loop approximation, and show that they coincide with the transformations on the supergravity side. These transformations are powerful in restricting the forms of the effective actions of probe D-branes in the fixed backgrounds of source D-branes. Furthermore, our formalism enables us to extend the concept of (generalized) conformal symmetry to arbitrary configurations of D-branes, which can still be used to restrict the dynamics of D-branes. For such general configurations, however, it cannot be endowed a simple classical space-time interpretation at least in the static gauge adopted in the present formulation of D-branes.Comment: 26 pages, no figure

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

"Cognitive bias modification" als mögliche Add-on-Therapie bei Depression: Stand der Forschung [Cognitive bias modification as possible add-on therapy for depression: State of research]

Contains fulltext : 203567.pdf (publisher's version ) (Open Access)Depression ist eine der häufigsten psychischen Erkrankungen, mit oft chronischem Verlauf und schwierig zu behandeln. Zusätzliche Interventionen, die auf spezielle Risikofaktoren abzielen, könnten neue Behandlungsmöglichkeiten bieten. Vielversprechend sind Trainingsprogramme, die automatische kognitive Prozesse und Verzerrungen beeinflussen. In den letzten Jahren wurden computergestützte Trainings entwickelt ("Cognitive-bias-modification"[CBM]-Programme), die genau auf diese Prozesse abzielen und zukünftig einfach als "Add-on" in die psychotherapeutische Praxis implementiert werden könnten. Im Folgenden wird der Stand der Forschung dargestellt und anhand eines eigenen klinischen Versuchs der detaillierte Aufbau aktueller Studien verdeutlicht.6 p

Combining dorsolateral prefrontal repetitive transcranial magnetic stimulation and attentional bias modification does not attenuate maladaptive attentional processing in dysphoric students

Contains fulltext : 203548.pdf (Publisher’s version ) (Open Access)2 p

Alcohol homograph priming in alcohol-dependent inpatients

Item does not contain fulltextAim: Alcohol dependency is characterized by alcohol-related interpretation biases (IBs): Individuals with high levels of alcohol consumption generate more alcohol-related than alcohol-unrelated interpretations in response to ambiguous alcohol-related cues. However, a response bias could be an alternative account, meaning that individuals with high levels of alcohol consumption generate more alcohol-related IBs because of a greater baseline tendency to endorse alcohol-related responses. Methods: To test this alternative explanation, the present study employed a homograph-priming task, reliability of which was also examined. The sample included 577 clinically diagnosed alcohol-dependent inpatients and 61 control inpatients. Participants completed a homograph priming task (primes: homographs with and without an alcohol-related meaning, target words: alcohol and soft drinks) before commencing their behavioral cognitive treatment at a rehabilitation clinic. Results: Contrary to our expectations, we did not find an enhanced priming effect in alcohol-dependent inpatients. Moreover, there was no correlation between the priming score and levels of harmful drinking (AUDIT scores). Conclusions: The data provide limited support for the existence of alcohol-related IBs, possibly because of the low reliability of the priming task, the features of the task, and the study’s design.8 p

Planning for PARADISEC

PARADISEC is a collaborative digital research resource set up by the University of Sydney, the University of Melbourne and the Australian National University in 2003, with funding from the Australia Research Council's Linkage Infrastructure Equipment and Facilities scheme. Conceived and created in cyberspace, the project locates its digitisation equipment at the University of Sydney, its website at ANU, and metadata database at the University of Melbourne, with researcher contributions from all three Universities. Current planning issues concern provision of appropriate levels of digital rights management and access for the many stakeholder communities located throughout the Asia-Pacific region. This presentation outlines the principles that have guided us in planning and implementation of PARADISEC.Department of Communications, Information Technology and the Arts Australian Research Counci

Effect of cognitive bias modification-memory on depressive symptoms and autobiographical memory bias: Two independent studies in high-ruminating and dysphoric samples

Item does not contain fulltextMemory bias is a risk factor for depression. In two independent studies, the efficacy of one CBM-Memory session on negative memory bias and depressive symptoms was tested in vulnerable samples. We compared positive to neutral (control) CBM-Memory trainings in highly-ruminating individuals (N=101) and individuals with elevated depressive symptoms (N=100). In both studies, participants studied positive, neutral, and negative Swahili words paired with their translations. In five study-test blocks, they were then prompted to retrieve either only the positive or neutral translations. Immediately following the training and one week later, we tested cued recall of all translations and autobiographical memory bias; and also measured mood, depressive symptoms, and rumination. Retrieval practice resulted in training-congruent recall both immediately after and one week after the training. Overall, there was no differential decrease in symptoms or difference in autobiographical memory bias between the training conditions. In the dysphoric but not in the high-ruminating sample, the positive training resulted in positive autobiographical bias only in dysphoric individuals with positive pre-existing bias. We conclude that one session of positive retrieval-based CBM-Memory may not be enough to yield symptom change and affect autobiographical memory bias in vulnerable individuals.17 p