3,636 research outputs found
Twistor description of spinning particles in AdS
The two-twistor formulation of particle mechanics in D-dimensional anti-de Sitter space for D=4,5,7, which linearises invariance
under the AdS isometry group Sp(4;K) for K=R,C,H,, is generalized to the massless N-extended ``spinning particle''. The twistor
variables are gauge invariant with respect to the initial N local worldline supersymmetries; this simplifies aspects of the quantum theory such as
implications of global gauge anomalies. We also give details of the two-supertwistor form of the superparticle, in particular the massive
superparticle on AdS5
Impacts of Unattended Train Operations (UTO) on Productivity and Efficiency in Metropolitan Railways
Urban metro subway systems (metros) around the world are choosing increasing levels of automation for new and existing lines: the global length of metro lines capable of unattended train operation (UTO) is predicted to triple in the next 10 years. Despite significant investment in this technology, empirical evidence for the financial and service quality impacts of UTO in metros remains scarce. This study used questionnaires and semistructured interviews with the Community of Metros and Nova Group benchmarking groups to assemble emerging evidence of how automation affected costs, staffing, service capacity, and reliability. The results from an analysis of data from 23 lines suggested that UTO could reduce staff numbers by 30% to 70%, with the amount of wage cost reduction depending on whether staff on UTO lines were paid more. On the basis of the experience of seven metros, the capital costs of lines capable of UTO were higher, but the internal rate of return had been estimated by two metros at 10% to 15%. Automated lines were capable of operating at the highest service frequencies of up to 42 trains per hour, and the limited available data suggested that automated lines were more reliable. The findings indicated that UTO was a means to a more flexible and reliable operating model that could increase metro productivity and efficiency. The study identified important work needed to understand the impacts of UTO and identify where statistical analyses would add value once sufficiently large data sets became available
Foot health education for people with rheumatoid arthritis
Foot problems for people with rheumatoid arthritis (RA) are common resulting in significant pain, activity restriction and reduced quality of life. Provision of information and health education in respect of foot health would therefore seem to be an essential aspect of foot health management for people with RA, in order to maintain their foot health and overall well being. Although educational resources exist for this group of people, their exact needs and preferred methods of receiving education about foot health have not been formally sought. The aim of this body of work was to investigate patients’ and podiatrists’ perspectives of current foot health education provision for people with RA in the UK; firstly aiming to identify any evidence to support the use of foot health education, then exploring patient and podiatry practitioner experiences of foot health education provision. This thesis therefore presents seven works published between 2011 and 2017 that explore the perceptions of people with RA and podiatrists about foot health education provision in the UK. This body of work has been critically reviewed through; personal reflection of the author’s perceptions of patient education and in the context of the work within the public domain. The methodological approaches used, the wider impact of the work and its’ translation into practice have been critically evaluated through analysis of citation/download and Altmetric data and review of the current literature, demonstrating the works’ broad utilisation and impact. This work demonstrates an original and distinctive contribution to research design within the podiatry profession, the understanding of foot health education needs of people with RA and the continuing significant burden that diminished foot health has on this population of people. Overall, the publications within this thesis have culminated in the identification of the need for future research to develop a foot-health related educational needs analysis tool that will facilitate a more timely and tailored approach to FHE provision
The Radiative Corrections to the Mass of the Kink Using an Alternative Renormalization Program
In this paper we compute the radiative correction to the mass of the kink in
theory in 1+1 dimensions, using an alternative renormalization
program. In this newly proposed renormalization program the breaking of the
translational invariance and the topological nature of the problem, due to the
presence of the kink, is automatically taken into account. This will naturally
lead to uniquely defined position dependent counterterms. We use the mode
number cutoff in conjunction with the above program to compute the mass of the
kink up to and including the next to the leading order quantum correction. We
discuss the differences between the results of this procedure and the
previously reported ones.Comment: 8 pages, 2 figures. arXiv admin note: substantial text overlap with
arXiv:0806.036
Simple and Nearly Optimal Polynomial Root-finding by Means of Root Radii Approximation
We propose a new simple but nearly optimal algorithm for the approximation of
all sufficiently well isolated complex roots and root clusters of a univariate
polynomial. Quite typically the known root-finders at first compute some crude
but reasonably good approximations to well-conditioned roots (that is, those
isolated from the other roots) and then refine the approximations very fast, by
using Boolean time which is nearly optimal, up to a polylogarithmic factor. By
combining and extending some old root-finding techniques, the geometry of the
complex plane, and randomized parametrization, we accelerate the initial stage
of obtaining crude to all well-conditioned simple and multiple roots as well as
isolated root clusters. Our algorithm performs this stage at a Boolean cost
dominated by the nearly optimal cost of subsequent refinement of these
approximations, which we can perform concurrently, with minimum processor
communication and synchronization. Our techniques are quite simple and
elementary; their power and application range may increase in their combination
with the known efficient root-finding methods.Comment: 12 pages, 1 figur
Quantum states on supersymmetric minisuperspace with a cosmological constant
Spatially homogeneous models in quantum supergravity with a nonvanishing
cosmological constant are studied. A class of exact nontrivial solutions of the
supersymmetry and Lorentz constraints is obtained in terms of the Chern-Simons
action on the spatially homogeneous 3-manifold, both in Ashketar variables
where the solution is explicit up to reality conditions, and, more concretely,
in the tetrad-representation, where the solutions are given as integral
representations differing only by the contours of integration. In the limit of
a vanishing cosmological constant earlier exact solutions for Bianchi type IX
models in the tetrad-representation are recovered and additional asymmetric
solutions are found.Comment: 14 pages, late
A survey of people with foot problems related to rheumatoid arthritis and their educational needs
Background
Up to 50% of people with rheumatoid arthritis (RA) have foot symptoms at diagnosis, hence early foot health intervention is recommended and this should include patient education. This study identifies, for the first time, the foot health education (FHE) needs of people with RA.
Methods
An online survey of people with RA (n = 543) captured quantitative data in relation to the aims, methods of delivery, content, timing and accessibility of FHE.
Results
The majority concurred about the aims of FHE. Verbal delivery and websites were the most common methods. Written and verbal FHE were perceived to be the most effective methods. The point of diagnosis was the preferred time to receive it. Lack of access to FHE included minimal focus on foot health during consultations by both health practitioners and patients with RA. Participant gender, age, disease duration and living situation had a statistically significant influence on the results.
Conclusion
Foot health education is rarely considered within the medical consultation. There is a lack of patient and/or health professional awareness of this need with a detrimental impact on foot health. Patients require health professionals to identify their foot education health needs. Tailored foot health education should begin at initial diagnosis
Use of clinical guidelines: Perspectives from clinicians in paediatric and maternity hospitals in Kabul, Afghanistan
© 2015, World Health Organization. All rights reserved. This study explored the perceived value, role and reported use of clinical guidelines by clinicians in urban paediatric and maternity hospital settings, and the effect of current implementation strategies on clinician attitudes, knowledge and behaviour. A total of 63 clinicians from 7 paediatric and maternity hospitals in Kabul, Afghanistan participated in structured focus groups; content analysis methodology was used for identification and analysis of key themes. Seven sets of guidelines, protocols or standards were identified (including 5 WHO-endorsed guidelines). However, most are failing to achieve high levels of use. Factors associated with guideline use included: clinician involvement in guideline development; multidisciplinary training; demonstrable results; and positive clinician perceptions regarding guideline quality and contextual appropriateness. Implementation activities should fulfil 3 major objectives: promote guideline awareness and access; stimulate motivation among clinical guideline users; and actively facilitate adherence to guidelines
- …