Twisted Electromagnetic Modes and Sagnac Ring-Lasers

A new approximation scheme, designed to solve the covariant Maxwell equations inside a rotating hollow slender conducting cavity (modelling a ring-laser), is constructed. It is shown that for well-defined conditions there exist TE and TM modes with respect to the longitudinal axis of the cavity. A twisted mode spectrum is found to depend on the integrated Frenet torsion of the cavity and this in turn may affect the Sagnac beat frequency induced by a non-zero rotation of the cavity. The analysis is motivated by attempts to use ring-lasers to measure terrestrial gravito-magnetism or the Lense-Thirring effect produced by the rotation of the Earth.Comment: LaTeX 31 pages, 3 Figure

Quantifying, Understanding and Predicting Differences Between Planned and Delivered Dose to Organs at Risk in Head & Neck Cancer Patients Undergoing Radical Radiotherapy to Promote Intelligently Targeted Adaptive Radiotherapy

Introduction: Radical radiotherapy (RT) is an effective but toxic treatment for head and neck cancer (HNC). Contemporary radiotherapy techniques sculpt dose to target disease and avoid organs at risk (OARs), but anatomical change during treatment mean that the radiation dose delivered to the patient – delivered dose (DA), is different to that anticipated at planning – planned dose (DP). Modifying the RT plan during treatment – Adaptive Radiotherapy (ART) – could mitigate these risks by reducing dose to OARs. However, clinical data to guide patient selection for, and timing of ART, are for lacking. Methods: 337 patients with HNC were recruited to the Cancer Research UK VoxTox study. Demographic, disease and treatment data were collated, and both DP and DA to organs at risk (OARs) were computed from daily megavoltage CT image guidance scans, using an open-source deformable image registration package (Elastix). Toxicity data were prospectively collected. Relationships between DP, DA and late toxicities were investigated with univariate, and logistic regression normal tissue complication probability (NTCP) modelling approaches. A sub-study of VoxTox recruited 18 patients who had MRI scans before RT fractions 1, 6, 16, and 26. Changes in salivary gland volumes and relative apparent diffusion coefficient (ADC) values were measured and related to toxicity events. Results: Spinal cord dose differences were small, and not predicted by weight loss or shape change. Mean DA to all other OARs was higher than DP; factors predicting higher DA included primary disease site, concomitant therapy, shape change and advanced neck disease. Nine patients (3.7%) saw DA>DP by 2Gy to more than half of the OARs assessed. These patients all had received bilateral neck RT for N-stage 2b oropharyngeal cancer. Strong uni- and multivariate relationships between OAR dose and toxicity were seen. Differences between DA and DP-based dose-toxicity models were minimal, and not statistically significant. On MRI, both parotid and submandibular glands shrank during treatment, whilst relative ADC rose. Relationships with toxicity were inconclusive. Conclusions: Small differences between OAR DP and DA mean that DA-based toxicity prediction models confer negligible additional benefit at the population level. Factors such as primary disease sub-site, concomitant systemic therapy, staging and shape change may help to select the patients that do develop clinically significant dose differences, and would benefit most from ART for toxicity reduction

African portfolio entrepreneurship and the creation of jobs

Purpose The purpose of this paper is to focus on large-scale portfolio entrepreneurship and its impact on the creation of stable wage employment in African economies. Design/methodology/approach The three studies focussed on Egypt, Uganda, and Malawi were all exploratory, inductive, and qualitative studies, which involved semi-structured interviews with 65 entrepreneurial founders of some of these countries’ most prominent business portfolios between 2009 and 2012. The data were collected through face-to-face interviews, which lasted between one and four hours, with the founders of each of these portfolios. Findings This inductive and qualitative study finds a connection between the creation of stable wage-paying jobs and portfolio entrepreneurship in three countries, representing three of the four different archetypal African economies. It also finds a strong connection between the development of new industries and portfolio entrepreneurship. Practical implications The practical and societal implications of these findings are incredibly important. The current and looming shortage of stable wage employment in Africa is reaching calamitous proportions. The growth in religion-affiliated terrorism and high-risk economic migration to Europe can be directly related to the lack of employment opportunities in African nations. The findings indicate that portfolio entrepreneurs are major players in the creation of such employment opportunities and government policies focussing on this area, as compared to focussing solely on SMEs, may be more effective in mitigating some of the drivers for emigration and terrorism. Originality/value This is the only study of its kind that investigates the role of large-scale portfolio entrepreneurship in the growth of employment opportunities in Africa

Using grounded theory to inform the design of energy interventions for the workplace

Much work has been published on using technological interventions to motivate reductions in home energy consumption. These interventions have produced promising results, but typically focus on emphasising the financial benefits of reductions in consumption to users. Motivating employees to reduce their consumption of energy in the workplace is more problematic, as they are typically not responsible for energy costs. There has been very little work to date addressing energy interventions in the workplace, and indeed, there are many challenges in doing so. This paper presents an overview of the initial user-centred design stage of a large energy research project called Electro-Magnates. Three day-long workshops were run with a total of 65 participants from 5 universities and a number of representatives from industry. The workshops’ main focus was understanding behaviour change in organisations in an energy resource and usage context, supported by designing a 12 month intervention. Audio and design task accounts were transcribed and analysed using the grounded theory approach with the developed theory forming the design requirements and implications for the Electro-Magnates intervention software. Our findings identified some of the key concepts for inclusion in a workplace energy intervention; incentivisation, openness and management buy-in

Feature Tracking Cardiac Magnetic Resonance via Deep Learning and Spline Optimization

Feature tracking Cardiac Magnetic Resonance (CMR) has recently emerged as an area of interest for quantification of regional cardiac function from balanced, steady state free precession (SSFP) cine sequences. However, currently available techniques lack full automation, limiting reproducibility. We propose a fully automated technique whereby a CMR image sequence is first segmented with a deep, fully convolutional neural network (CNN) architecture, and quadratic basis splines are fitted simultaneously across all cardiac frames using least squares optimization. Experiments are performed using data from 42 patients with hypertrophic cardiomyopathy (HCM) and 21 healthy control subjects. In terms of segmentation, we compared state-of-the-art CNN frameworks, U-Net and dilated convolution architectures, with and without temporal context, using cross validation with three folds. Performance relative to expert manual segmentation was similar across all networks: pixel accuracy was ~97%, intersection-over-union (IoU) across all classes was ~87%, and IoU across foreground classes only was ~85%. Endocardial left ventricular circumferential strain calculated from the proposed pipeline was significantly different in control and disease subjects (-25.3% vs -29.1%, p = 0.006), in agreement with the current clinical literature.Comment: Accepted to Functional Imaging and Modeling of the Heart (FIMH) 201

Big Data and Strategy: Theoretical Foundations and New Opportunities

The digitization of products, processes, and business models—and the corresponding explosion of big data—has led to an evolution within business organizations. Reaching far beyond information technology’s traditional role in business strategy, the implications of this big data phenomenon are considered through an exploration into what big data is, how it is currently being used by existing firms, and how it factors into strategic thinking. As different organizational approaches have developed toward big data, we use resource-based theory and organizational learning as anchoring perspectives to link this phenomenon with traditional strategic management. We also identify four avenues for future scholarship as the nature of business moves increasingly digital

How do trainee doctors learn about research? Content analysis of Australian specialist colleges' intended research curricula

Objectives: Patients do better in research-intense environments. The importance of research is reflected in the accreditation requirements of Australian clinical specialist colleges. The nature of college-mandated research training has not been systematically explored. We examined the intended research curricula of Australian trainee doctors described by specialist colleges, their constructive alignment and the nature of scholarly project requirements. Design: We undertook content analysis of publicly available documents to characterise college research training curricula. Setting: We reviewed all publicly accessible information from the websites of Australian specialist colleges and their subspecialty divisions. We retrieved curricula, handbooks and assessment-related documents. Participants: Fifty-eight Australian specialist colleges and their subspecialty divisions. Primary and secondary outcome measures: Two reviewers extracted and coded research-related activities as learning outcomes, activities or assessments, by research stage (using, participating in or leading research) and competency based on Bloom’s taxonomy (remembering, understanding, applying, analysing, evaluating, creating). We coded learning and assessment activities by type (eg, formal research training, publication) and whether it was linked to a scholarly project. Requirements related to project supervisors’ research experience were noted. Results: Fifty-five of 58 Australian college subspecialty divisions had a scholarly project requirement. Only 11 required formal research training; two required an experienced research supervisor. Colleges emphasised a role for trainees in leading research in their learning outcomes and assessments, but not learning activities. Less emphasis was placed on using research, and almost no emphasis on participation. Most learning activities and assessments mapped to the ‘creating’ domain of Bloom’s taxonomy, whereas most learning outcomes mapped to the ‘evaluating’ domain. Overall, most research learning and assessment activities were related to leading a scholarly project. Conclusions: Australian specialist college research curricula appear to emphasise a role for trainees in leading research and producing research deliverables, but do not mandate formal research training and supervision by experienced researchers

Internet Distribution of Spacecraft Telemetry Data

Remote Access Multi-mission Processing and Analysis Ground Environment (RAMPAGE) is a Java-language server computer program that enables near-real-time display of spacecraft telemetry data on any authorized client computer that has access to the Internet and is equipped with Web-browser software. In addition to providing a variety of displays of the latest available telemetry data, RAMPAGE can deliver notification of an alarm by electronic mail. Subscribers can then use RAMPAGE displays to determine the state of the spacecraft and formulate a response to the alarm, if necessary. A user can query spacecraft mission data in either binary or comma-separated-value format by use of a Web form or a Practical Extraction and Reporting Language (PERL) script to automate the query process. RAMPAGE runs on Linux and Solaris server computers in the Ground Data System (GDS) of NASA's Jet Propulsion Laboratory and includes components designed specifically to make it compatible with legacy GDS software. The client/server architecture of RAMPAGE and the use of the Java programming language make it possible to utilize a variety of competitive server and client computers, thereby also helping to minimize costs