348 research outputs found
The drivers and timescales of solar wind-magnetosphere-Ionosphere coupling in global MHD simulations
The interaction between the solar wind and the terrestrial magnetosphere-ionosphere system is highly dynamic and non-linear, strongly influencing conditions in near-Earth space. Understanding the coupling between each component of the system is crucial to mitigating societal effects, known as space weather. Global magnetohydrodynamic (MHD) simulations are an invaluable tool in studying this interaction. This thesis entails the use of the Gorgon MHD code for simulating the Earth’s magnetosphere. An updated version of the code is presented, including a newly developed ionosphere module which is tested and benchmarked to validate its proper coupling to the magnetosphere.
The model is applied to study the effect of the geomagnetic dipole tilt angle on magnetopause reconnection and ionospheric current systems. The location of the reconnection line is identified for tilt angles up to 90°, with reconnection found to be weaker and more unsteady at large tilt angles. The tilt introduces a North-South asymmetry driving more FAC in the sunward-facing hemisphere, highlighting the sensitivity to onset time in the potential impact of a severe space weather event.
An idealised example of such an event is then simulated by impacting the magnetosphere with an interplanetary shock. The location and intensity of dayside reconnection is found to be highly time-dependent following impact, with reconnection enhanced in the vicinity of the shock. These results suggest that steady models of reconnection may not be reliable immediately after onset.
Finally, an extended version of the code is implemented to simulate a real geomagnetic storm. The key response timescales of the magnetosphere-ionosphere system to the varying solar wind are investigated, and found to be consistent with those of global convection, being sensitive to the particular mode of driving. It is shown that Gorgon is a capable space weather modelling tool, forming a crucial step towards future operational forecasting purposes.Open Acces
Raising the Status of Music and the Musician at the Academy of Ancient Music in Eighteenth-Century London
Modelling the impact of referral guideline changes for mild dyskaryosis on colposcopy services in England
Objectives: This model examines the effects of changing referral strategies within the established structure of NHS cervical screening driven colposcopy practice. It considers the effects of the new strategy on colposcopy workload, patient waiting times, and associated costs and health benefits.
Methods: By postal survey, the current operational strategies of colposcopy services were established by questionnaire with respect to referral practices and management protocols. After first-cut piloting, and utilising published and original research, a Markovian model was constructed, and the impact of the new strategy was determined on colposcopy workload and patient waiting times for three hypothetical clinic types. Expected costs and benefits of the new policy were assessed through the adaptation of a previous ScHARR cervical screening model.
Results: Clinic workload is expected to increase by between 21% and 35% within three years of the policy change, depending on clinic efficiency in other areas; the majority of this impact would be seen within the first year. It is predicted that particularly inefficient clinics would struggle to meet the existing waiting time requirements for women referred with low-grade disease, owing to the increased level of workload seen throughout the patient pathway as a result of the implementation of the new policy.
The impact of the new policy can, however, be mitigated through improving the efficiency of existing clinics, by altering policies relating to surveillance of low grade disease, post-treatment follow-up, treatment policy (whether or not treatment is performed at the initial colposcopy visit), and through adherence to national guidelines.
A cost-effectiveness analysis using the ScHARR liquid-based cytology model suggests that the policy change is likely to be have a cost per quality-adjusted lifeyear gained of between £1,400 and £5,500 per quality-adjusted life-year gained (excluding the costs of follow-up), which would be deemed acceptable to organisations such as the National Institute for Health and Clinical Excellence
Benjamin Cooke (1734-93), Composer and Academician:Science, Ancient Authority and the Advancement of English Music
As organist of Westminster Abbey and conductor of the Academy of Ancient Music for most of the second half of the eighteenth century, Benjamin Cooke constitutes an important yet now forgotten figure. Extant Cooke manuscripts preserved in the Cooke Collection at the Royal College of Music represent an extensive though hitherto little examined source through which this study is made possible. In Cooke's compositions, musical tastes and theoretical writings may be perceived an all encompassing philosophy according to which not only the materials of music but even elements of musical style are seen to be governed by a priori principles. In this approach may be observed a philosophy consistent with wider eighteenth-century thinking, according to which antiquity and science were viewed as a source of universal and immutable truth.
Chapters 1 and 2 of this thesis set out the intellectual background to Cooke's theoretical writings and assess the significance of his unpublished treatise Musical Conjectures. Here we see how Cooke used his learning to resolve musical issues of his day (such as tuning) and to hone critical tools for the assessment of music. Chapter 3 provides a survey of the Cooke Collection. Here Cooke's editing of early music reveals an aspiration to map the musical past in order to establish terms of reference for the present, knowledge which impinged upon his own composing. Chapters 4 and 5 survey a representative sample of Cooke's compositions, culminating with an in-depth examination of two defining works, The Morning Hymn and Collins's Ode. Although these reveal a pronounced debt to music of the previous 200 years, they also exhibit a profound sense of innovation and creativity in style and language. In this we find an aspiration to advance music in a manner consistent with later eighteenth-century imperatives for simplicity, whilst retaining the gravitas and substance inherent in earlier styles
Tying It All Together: Implications for Classrooms, Schools, and Districts
Ryan Flessner, Kenneth Zeichner, and Kalani Eggington\u27s contribution to Creating Equitable Classrooms through Action Researc
Structural and functional differentiation of teleost skeletal muscle
The lateral musculature of elvers is differentiated into two fibre type on the basis of alkaline-labile (pH 10.2) myofibrillar ATPase activity. Slow muscle forms a relatively homogeneous fibre population, whereas fast muscle shows a heterogeneity with respect to both fibre size, and position in the myotome. The low aerobic capacity of slow fibres reflects the energetic requirement of anguilliform locomotion. A morphological continuum of myogenic cells occurs within mature; differentiated myotomal muscle similar to that described for embryonic myogenesis. No evidence could be found for regional growth nodes. Small fast fibres ( <100µm2) represent immature, but differentiated fibres undergoing hypertrophy. There is considerable variation in the capillary supply to both fast and slow muscle, and between homologous muscle off different species. Methods are described to determine the minimum sample size required for a stable, reproducible parameter estimate, and to assess the orientation of the capillary network. This is shown to be highly anisotropic. Capillary volume and surface densities are thought to be the most appropriated indices to use with fish muscle. The springs migration of elvers is shown to be a mixed population, of similar annual composition. The main migratory wave are true post-metamorphic, juvenile eels. There is a partial (Precht type 3) compensation in VO2 on acclimation to 10° and 29°C. The extent of the physiological acclimation reflects the environmental constraints of the migration. Differences in structure and complexity of multiple and focal innervation were investigated using fast muscle from representative teleosts. Endplate structure is similar in both types. Cod ventral spinal nerves have fewer motor, but more sensory axons than homologous nerves in eel. A novel way of visualizing the extent of inter- end intra segmental branching of nerves, intracellular marking of nerve routes with cobalt, reveals extensive branching in cod mytomes and cross-innervation between at least 3 segments. In cel, branching is restricted to a single mytome. These results reflect the mechanical and nervous control over the locomotory waveform
Enhancing Teacher Education and Community Learning Center Programs through Critical Participatory Action Research
This paper describes the impact of using Critical Participatory Action Research (CPAR) to enhance a campus-community partnership. The key stakeholders, who are also the participants, share how learning from the reflective journals, collaborative sessions, and interview data analysis transformed their practice. The collaborative partnership was designed to allow prospective teachers from a School of Education at a U.S. liberal arts college the opportunity to teach Diverse language learners (DLLs) who were attending a summer program at a nearby community learning center. The teacher educators responsible for teaching the prospective teachers, the director of the community learning center, and a student researcher joined the project as collaborative participant researchers. Together they analyzed the data collected from various participating groups which included their own work and reflections, as well as those of the prospective teachers and prevention specialists who were employed by the community learning center. The findings from this study revealed that all participants benefited from the campus-community partnership because it was built on trust, mutual respect, reciprocity, and the use of shared language among key stakeholders. This CPAR project provides specific ideas and steps implemented to develop a well-functioning and reflective partnership between a community learning center and a local college. Examples of the specific praxis involved in such partnerships are often absent from the literature
PCN115 COST UTILITY ANALYSIS OF 90Y-IBRITUMOMAB TIUXETAN FOLLOWING FIRST-LINE CHEMOTHERAPY COMPARED TO NO FOLLOW-UP IN PATIENTS WITH STAGE III OR IV FOLLICULAR LYMPHOMA IN SPAIN
A Pilot Study of Value of Information Analysis to Support Research Recommendations for the National Institute for Health and Clinical Excellence
Background - This project developed as a result of the activities of the Research Teams at the Centre for Health Economics, University of York, and ScHARR at the University of Sheffield in the methods and application of decision analysis and value of information analysis as a means of informing the research recommendations made by NICE, as part of its Guidance to the NHS in England and Wales, and informing the deliberations of the NICE Research and Development Committee. Objectives - The specific objectives of the pilot study were to: • Demonstrate the benefits of using appropriate decision analytic methods and value of information analysis to inform research recommendations. • Establish the feasibility and resource implications of applying these methods in a timely way, to inform NICE. • Identify critical issues and methodological challenges to the use of value of information methods for research recommendations (with particular regard to the new reference case as a suitable basis for this type of analysis).
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