Bogomol’nyi equations on constant curvature spaces

This thesis is concerned with the anti-self-dual Yang-Mills equations and their reductions to Bogomol’nyi equations on constant curvature spaces. Chapters 1 and 2 contain introductory material. Chapter 1 discusses the origin of the equations in particle physics and their role in integrable systems. Chapter 2 describes the equations and the reduction process and outlines the construction of solutions via the twistor transform. In Chapter 3 we consider Bogomol’nyi equations on (2 + 1)-dimensional manifolds and show that for constant curvature space-times the equations are integrable and consider solutions in the negative scalar curvature case. In Chapter 4 we cover the negative scalar curvature case in more detail, constructing a number of soliton solutions including non-trivial scattering and consider the zero-curvature limit. In Chapter 5 we consider Bogomornyi equations in 3- diniensional hyperbolic space, derive an ansatz for solutions of the equation and use it to construct a number of new solutions. Chapter 6 contains concluding remarks

Aphasia rehabilitation: Does generalisation from anomia therapy occur and is it predictable? A case series study

Introduction: The majority of adults with acquired aphasia have anomia which can respond to rehabilitation with cues. However, the literature and clinical consensus suggest change is usually limited to treated items. We investigated the effect of an experimentally controlled intervention using progressive cues in the rehabilitation of noun retrieval/production in 16 participants with chronic aphasia. Method: Participants were sub-divided relative to the group according to performance on semantic tasks (spoken/written word to picture matching) and phonological output processing (presence/absence of word length effect and proportion of phonological errors in picture naming) in order to investigate outcome in relation to language profile. Cueing therapy took place weekly for 8 weeks. Results: Intervention resulted in significant improvement on naming treated items for 15/16 participants, with stable performance on control tasks. Change occurred at the point of intervention and not during pre-therapy assessments. We predicted particular patterns of generalisation which were upheld. Only participants classified as having relatively less of a semantic difficulty and more of a phonological output deficit demonstrated generalisation to untreated items. Outcome did not relate to traditional aphasia classification. Conclusion: A cueing hierarchy can improve word retrieval/production for adults with aphasia. In some cases generalisation to untreated items also occurs. The study demonstrates that the results of behavioural testing can be used to guide predictions of recovery with intervention. © 2013 Elsevier Ltd

Preliminary Real-World Evaluation of an Intervention for Parents of Adolescents: The Open Door Approach to Parenting Teenagers (APT)

Most parenting interventions report high dropout rates for parents who exhibit clinically high levels of stress and/or are parents of adolescents with severe emotional and/or behavioral difficulties. The objective of this preliminary study was to evaluate the feasibility and real-world effectiveness of the Open Door Approach to Parenting Teenagers (APT), a six-session individually delivered face-to-face intervention for typically hard to engage parents of 11 to 21-year-olds. A one-group, pre-post evaluation design was adopted due to the naturalistic clinic-based setting of the study. Participants were 279 parents reporting clinical levels of stress relating to parenting an adolescent. Parents receiving the APT intervention demonstrated lower dropout rates than other parenting programs and reported high scores across several items relating to service satisfaction. The APT intervention was associated with significant reductions in parental stress and improvements in parent-adolescent relationships immediately post-intervention. Findings suggest that parents found the APT intervention acceptable and beneficial, and further suggest that the intervention is feasible and effective in retaining hard to engage parents. Moreover, preliminary findings suggest that the APT intervention is a promising intervention that may support parents who fail to engage in group programs. However, further research is required to establish the efficacy of the intervention

Cognitive or behavioural interventions (or both) to prevent or mitigate loneliness in adolescents, adults, and older adults

This is a protocol for a Cochrane Review (intervention). The objectives are as follows: To examine the effects of structured psychological interventions, based on cognitive behavioural therapy (CBT) techniques, compared to all comparators on loneliness in adolescents, adults, and older adults with diagnoses of common mental disorders, or at risk of loneliness. To examine the effects of structured psychological interventions, based on CBT techniques, compared to all comparators on depression severity, anxiety severity, social connectedness, or quality of life in adolescents, adults, and older adults, with diagnoses of common mental disorders, or at risk of loneliness

The EPICS Software Framework Moves from Controls to Physics

The Experimental Physics and Industrial Control System (EPICS), is an open-source software framework for high-performance distributed control, and is at the heart of many of the world’s large accelerators and telescopes. Recently, EPICS has undergone a major revision, with the aim of better computing supporting for the next generation of machines and analytical tools. Many new data types, such as matrices, tables, images, and statistical descriptions, plus users’ own data types, now supplement the simple scalar and waveform types of the former EPICS. New computational architectures for scientific computing have been added for high-performance data processing services and pipelining. Python and Java bindings have enabled powerful new user interfaces. The result has been that controls are now being integrated with modelling and simulation, machine learning, enterprise databases, and experiment DAQs. We introduce this new EPICS (version 7) from the perspective of accelerator physics and review early adoption cases in accelerators around the world

Effects of syntactic cueing therapy on picture naming and connected speech in acquired aphasia

Language therapy for word-finding difficulties in aphasia usually involves picture naming of single words with the support of cues. Most studies have addressed nouns in isolation, even though in connected speech nouns are more frequently produced with determiners. We hypothesised that improved word finding in connected speech would be most likely if intervention treated nouns in usual syntactic contexts. Six speakers with aphasia underwent language therapy using a software program developed for the purpose, which provided lexical and syntactic (determiner) cues. Exposure to determiners with nouns would potentially lead to improved picture naming of both treated and untreated nouns, and increased production of determiner plus noun combinations in connected speech. After intervention, picture naming of treated words improved for five of the six speakers, but naming of untreated words was unchanged. The number of determiner plus noun combinations in connected speech increased for four speakers. These findings attest to the close relationship between frequently co-occurring content and function words, and indicate that intervention for word-finding deficits can profitably proceed beyond single word naming, to retrieval in appropriate syntactic contexts. We also examined the relationship between effects of therapy, and amount and intensity of therapy. We found no relationship between immediate effects and amount or intensity of therapy. However, those participants whose naming maintained at follow-up completed the therapy regime in fewer sessions, of relatively longer duration. We explore the relationship between therapy regime and outcomes, and propose future considerations for research

The interplay of local electron correlations and ultrafast spin dynamics in fcc Ni

The complex electronic structure of metallic ferromagnets is determined by a balance between exchange interaction, electron hopping leading to band formation, and local Coulomb repulsion. The interplay between the respective terms of the Hamiltonian is of fundamental interest, since it produces most, if not all, of the exotic phenomena observed in the solid state. By combining high energy and temporal resolution in femtosecond time-resolved X-ray absorption spectroscopy with ab initio time-dependent density functional theory we analyze the electronic structure in fcc Ni on the time scale of these interactions in a pump-probe experiment. We distinguish transient broadening and energy shifts in the absorption spectra, which we demonstrate to be caused by electron repopulation and correlation-induced modifications of the electronic structure, respectively. Importantly, the theoretical description of this experimental result hence requires to take the local Coulomb interaction into account, revealing a temporal interplay between band formation, exchange interaction, and Coulomb repulsion

Megahertz-rate ultrafast X-ray scattering and holographic imaging at the European XFEL

The advent of X-ray free-electron lasers (XFELs) has revolutionized fundamental science, from atomic to condensed matter physics, from chemistry to biology, giving researchers access to X-rays with unprecedented brightness, coherence and pulse duration. All XFEL facilities built until recently provided X-ray pulses at a relatively low repetition rate, with limited data statistics. Here, results from the first megahertz-repetition-rate X-ray scattering experiments at the Spectroscopy and Coherent Scattering (SCS) instrument of the European XFEL are presented. The experimental capabilities that the SCS instrument offers, resulting from the operation at megahertz repetition rates and the availability of the novel DSSC 2D imaging detector, are illustrated. Time-resolved magnetic X-ray scattering and holographic imaging experiments in solid state samples were chosen as representative, providing an ideal test-bed for operation at megahertz rates. Our results are relevant and applicable to any other non-destructive XFEL experiments in the soft X-ray range

Photon shot-noise limited transient absorption soft X-ray spectroscopy at the European XFEL

Femtosecond transient soft X-ray Absorption Spectroscopy (XAS) is a very promising technique that can be employed at X-ray Free Electron Lasers (FELs) to investigate out-of-equilibrium dynamics for material and energy research. Here we present a dedicated setup for soft X-rays available at the Spectroscopy & Coherent Scattering (SCS) instrument at the European X-ray Free Electron Laser (EuXFEL). It consists of a beam-splitting off-axis zone plate (BOZ) used in transmission to create three copies of the incoming beam, which are used to measure the transmitted intensity through the excited and unexcited sample, as well as to monitor the incoming intensity. Since these three intensity signals are detected shot-by-shot and simultaneously, this setup allows normalized shot-by-shot analysis of the transmission. For photon detection, the DSSC imaging detector, which is capable of recording up to 800 images at 4.5 MHz frame rate during the FEL burst, is employed and allows approaching the photon shot-noise limit. We review the setup and its capabilities, as well as the online and offline analysis tools provided to users