Wave Propagation in Relativistic Electron-Positron Plasmas

The study of wave propagation in a plasma provides an invaluable insight into the plasma's fundamental behaviour and structure. In this thesis we study wave propagation in relativistic electron-positron plasmas. The effects of the mass symmetry of the two species on the plasma system are investigated in a regime where the energy of the plasma particles is of the same order of magnitude as their rest energy

A managerial cognition perspective on the product innovation performance of Irish industry

Little is yet known about the reason(s) for the apparently poor product innovation performance of Irish companies. The findings of a small preliminary study carried out in the context of the present research (prompted by the discovery and re-interpretation of an under-exploited finding of an isolated and under-publicized study conducted a decade ago by O’Sullivan and Tomlin (1985)), suggested the significance of the manner in which the product innovation process is managed - but, perhaps more importantly, that ineffective management of the product innovation process may stem from ‘faulty thinking’ about product innovation and an inadequate understanding of the product realization process. A case was thus made for addressing the product innovation performance of indigenous Irish industry primarily in terms of ‘product realization performance’, for investigating the matter, initially, at least, at an organizational level, for using routine organizational product innovation practice as a focal point for the study and for adopting an overall managerial cognition perspective on the problem, the suggested way forward being the further exploration of the nature and effects of managers' beliefs and understanding of how the process of transforming product innovation ideas into marketable products might best be achieved. A model of cognition, practice and performance was proposed and tested using Irish-owned electronics firms as test case. The cognitive component of the model was based on a ‘top-down, knowledge-how, modified script concept using four core product realization activities and sixty-four principles of effective product innovation practice recommended by the international innovation literature as an a priority defined investigative agenda, a Bougon-grid based data elicitation framework and an analytical framework based on the work of Galambos el al and Langfield-Smith and Wirth. The test of the model generated a considerable number of statistically significant and other interesting findings. A number of conclusions were drawn and discussed

Esquisse des types de recherche dans le domaine de l’éducation relative à l’environnement

L’éducation relative à l’environnement (ERE) existe depuis quelque trente ans à titre d’instrument privilégié pour contribuer à résoudre ce qu’il est convenu d’appeler la crise écologique. Comme tout autre domaine de connaissances et d’intervention, celui de l’ERE n’est pas monolithique et son développement est jalonné par des conceptions et initiatives variées, notamment sur le plan de la recherche. Nous proposons ici une esquisse de ces initiatives, suivant les points de vue qui les animent..

Can the use of Bayesian analysis methods correct for incompleteness in electronic health records diagnosis data? Development of a novel method using simulated and real-life clinical data

Background Patient health information is collected routinely in electronic health records (EHRs) and used for research purposes, however, many health conditions are known to be under-diagnosed or under-recorded in EHRs. In research, missing diagnoses result in under-ascertainment of true cases, which attenuates estimated associations between variables and results in a bias towards the null. Bayesian approaches allow the specification of prior information to the model, such as the likely rates of missingness in the data. This paper describes a Bayesian analysis approach which aimed to reduce attenuation of associations in EHR studies focussed on conditions characterised by under-diagnosis. Methods Study 1: We created synthetic data, produced to mimic structured EHR data where diagnoses were under-recorded. We fitted logistic regression (LR) models with and without Bayesian priors representing rates of misclassification in the data. We examined the LR parameters estimated by models with and without priors. Study 2: We used EHR data from UK primary care in a case-control design with dementia as the outcome. We fitted LR models examining risk factors for dementia, with and without generic prior information on misclassification rates. We examined LR parameters estimated by models with and without the priors, and estimated classification accuracy using Area Under the Receiver Operating Characteristic. Results Study 1: In synthetic data, estimates of LR parameters were much closer to the true parameter values when Bayesian priors were added to the model; with no priors, parameters were substantially attenuated by under-diagnosis. Study 2: The Bayesian approach ran well on real life clinic data from UK primary care, with the addition of prior information increasing LR parameter values in all cases. In multivariate regression models, Bayesian methods showed no improvement in classification accuracy over traditional LR. Conclusions The Bayesian approach showed promise but had implementation challenges in real clinical data: prior information on rates of misclassification was difficult to find. Our simple model made a number of assumptions, such as diagnoses being missing at random. Further development is needed to integrated the method into studies using real-life EHR data. Our findings nevertheless highlight the importance of developing methods to address missing diagnoses in EHR data

Protocol: Are primary care consultations for insomnia associated with dementia in later life?

Insomnia has been defined as a difficulty initiating or maintaining sleep, leading to sleep that is either insufficient or unrefreshing. It is well-established that insomnia is more common in people with dementia, but it is not clear if insomnia predates dementia in these individuals. This latter question is an important one: if it can be shown that people with insomnia are more likely to develop dementia in later life, this may improve our ability to predict an individual’s dementia risk, and possibly to help manage that risk. Several recent studies have found a link between insomnia and later dementia, but typically give little information about the time between the onset of insomnia and the onset of dementia, raising the possibility that the insomnia is an early symptom of dementia, rather than a risk factor or potential cause of the disease. Furthermore, in some studies the link between insomnia and dementia becomes weaker when factors such as depression and sleeping tablet use are taken into account. The proposed study uses primary care records to learn whether people with dementia are more likely to have consulted with their general practitioner (GP) about insomnia 5-10 years earlier, compared to those who do not have dementia

Design of a randomized superiority trial of a brief couple treatment for PTSD.

Interpersonal difficulties are common among veterans with posttraumatic stress disorder (PTSD) and are associated with poorer treatment response. Treatment outcomes for PTSD, including relationship functioning, improve when partners are included and engaged in the therapy process. Cognitive-behavioral conjoint therapy for PTSD (CBCT) is a manualized 15-session intervention designed for couples in which one partner has PTSD. CBCT was developed specifically to treat PTSD, engage a partner in treatment, and improve interpersonal functioning. However, recent research suggests that an abbreviated CBCT protocol may lead to sufficient gains in PTSD and relationship functioning, and yield lower dropout rates. Likewise, many veterans report a preference for receiving psychological treatments through clinical videoteleconferencing (CVT) rather than traditional face-to-face modalities that require travel to VA clinics. This manuscript describes the development and implementation of a novel randomized controlled trial (RCT) that examines the efficacy of an abbreviated 8-session version of CBCT ("brief CBCT," or B-CBCT), and compares the efficacy of this intervention delivered via CVT to traditional in-person platforms. Veterans and their partners were randomized to receive B-CBCT in a traditional Veterans Affairs office-based setting (B-CBCT-Office), CBCT through CVT with the veteran and partner at home (B-CBCT-Home), or an in office-delivered, couple-based psychoeducation control condition (PTSD Family Education). This study is the first RCT designed to investigate the delivery of B-CBCT specifically to veterans with PTSD and their partners, as well as to examine the delivery of B-CBCT over a CVT modality; findings could increase access to care to veterans with PTSD and their partners