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Kevin Barraclough

Other affiliations: University of London
Bio: Kevin Barraclough is an academic researcher from University of Bristol. The author has contributed to research in topics: Polymyalgia rheumatica & Guideline. The author has an hindex of 16, co-authored 58 publications receiving 31563 citations. Previous affiliations of Kevin Barraclough include University of London.


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08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: These guidelines are designed to provide evidence-based advice for the assessment and diagnosis of GCA, for initial and further management and for monitoring of disease activity, complications and relapse.
Abstract: Scope and purpose GCA is the commonest of all the vasculitides. Visual loss occurs in up to one-fifth of patients, which may be preventable by prompt recognition and treatment [1,2]. The aim of these guidelines is to encourage the prompt diagnosis and management of GCA, with emphasis on the prevention of visual loss. Their scope is to provide evidence-based advice for the assessment and diagnosis of GCA, for initial and further management and for monitoring of disease activity, complications and relapse. This is a summary of the guidelines and the full guideline is available at Rheumatology online.

412 citations

Journal ArticleDOI
TL;DR: In this article, the authors report the 2015 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) recommendations for the management of polymyalgia rheumatica (PMR).
Abstract: Therapy for polymyalgia rheumatica (PMR) varies widely in clinical practice as international recommendations for PMR treatment are not currently available. In this paper, we report the 2015 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) recommendations for the management of PMR. We used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology as a framework for the project. Accordingly, the direction and strength of the recommendations are based on the quality of evidence, the balance between desirable and undesirable effects, patients' and clinicians' values and preferences, and resource use. Eight overarching principles and nine specific recommendations were developed covering several aspects of PMR, including basic and follow-up investigations of patients under treatment, risk factor assessment, medical access for patients and specialist referral, treatment strategies such as initial glucocorticoid (GC) doses and subsequent tapering regimens, use of intramuscular GCs and disease modifying anti-rheumatic drugs (DMARDs), as well as the roles of non-steroidal anti-rheumatic drugs and non-pharmacological interventions. These recommendations will inform primary, secondary and tertiary care physicians about an international consensus on the management of PMR. These recommendations should serve to inform clinicians about best practices in the care of patients with PMR.

244 citations

Journal ArticleDOI
TL;DR: These guidelines are designed to provide advice for the diagnosis of PMR, manage-ment and monitoring of disease activity, complications and relapse, using continued assessment and discouragement of hasty initial treatment.
Abstract: PMR is the most common inflammatory rheumaticdisease in the elderly and is one of the biggest indicationsfor long-term steroid therapy. There are difficulties indiagnosis, with heterogeneity in presentation, responseto steroids and disease course.The aim of these guidelines is a safe and specificdiagnostic process for PMR, using continued assessment,and discouragement of hasty initial treatment. Their scopeis to provide advice for the diagnosis of PMR, manage-ment and monitoring of disease activity, complicationsand relapse. The management of GCA is not coveredand is published separately.The full guideline is available at Rheumatology online.

204 citations

Journal ArticleDOI
01 May 2016-BMJ Open
TL;DR: Omission of text records from CPRD studies introduces bias that inflates outcome measures for recognised alarm symptoms, potentially reinforces clinicians’ views of the known importance of these symptoms, marginalising the significance of ‘low-risk but not no-risk’ symptoms.
Abstract: Objectives To estimate data loss and bias in studies of Clinical Practice Research Datalink (CPRD) data that restrict analyses to Read codes, omitting anything recorded as text Design Matched case–control study Setting Patients contributing data to the CPRD Participants 4915 bladder and 3635 pancreatic, cancer cases diagnosed between 1 January 2000 and 31 December 2009, matched on age, sex and general practitioner practice to up to 5 controls (bladder: n=21 718; pancreas: n=16 459) The analysis period was the year before cancer diagnosis Primary and secondary outcome measures Frequency of haematuria, jaundice and abdominal pain, grouped by recording style: Read code or text-only (ie, hidden text) The association between recording style and case–control status (χ2 test) For each feature, the odds ratio (OR; conditional logistic regression) and positive predictive value (PPV; Bayes’ theorem) for cancer, before and after addition of hidden text records Results Of the 20 958 total records of the features, 7951 (38%) were recorded in hidden text Hidden text recording was more strongly associated with controls than with cases for haematuria (140/336=42% vs 556/3147=18%) in bladder cancer (χ2 test, p<0001), and for jaundice (21/31=67% vs 463/1565=30%, p<00001) and abdominal pain (323/1126=29% vs 397/1789=22%, p<0001) in pancreatic cancer Adding hidden text records corrected PPVs of haematuria for bladder cancer from 40% (95% CI 35% to 46%) to 29% (26% to 32%), and of jaundice for pancreatic cancer from 128% (73% to 216%) to 63% (45% to 87%) Adding hidden text records did not alter the PPV of abdominal pain for bladder (codes: 014%, 013% to 016% vs codes plus hidden text: 014%, 013% to 015%) or pancreatic (023%, 021% to 025% vs 021%, 020% to 022%) cancer Conclusions Omission of text records from CPRD studies introduces bias that inflates outcome measures for recognised alarm symptoms This potentially reinforces clinicians’ views of the known importance of these symptoms, marginalising the significance of ‘low-risk but not no-risk’ symptoms

70 citations


Cited by
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TL;DR: In this paper, a new type of metallic structure has been developed that is characterized by having high surface impedance, which is analogous to a corrugated metal surface in which the corrugations have been folded up into lumped-circuit elements and distributed in a two-dimensional lattice.
Abstract: A new type of metallic electromagnetic structure has been developed that is characterized by having high surface impedance. Although it is made of continuous metal, and conducts dc currents, it does not conduct ac currents within a forbidden frequency band. Unlike normal conductors, this new surface does not support propagating surface waves, and its image currents are not phase reversed. The geometry is analogous to a corrugated metal surface in which the corrugations have been folded up into lumped-circuit elements, and distributed in a two-dimensional lattice. The surface can be described using solid-state band theory concepts, even though the periodicity is much less than the free-space wavelength. This unique material is applicable to a variety of electromagnetic problems, including new kinds of low-profile antennas.

4,264 citations

Journal ArticleDOI
TL;DR: VESTA as mentioned in this paper is a cross-platform program for visualizing both structural and volumetric data in multiple windows with tabs, including isosurfaces, bird's-eye views and two-dimensional maps.
Abstract: A cross-platform program, VESTA, has been developed to visualize both structural and volumetric data in multiple windows with tabs. VESTA represents crystal structures by ball-and-stick, space-filling, polyhedral, wireframe, stick, dot-surface and thermal-ellipsoid models. A variety of crystal-chemical information is extractable from fractional coordinates, occupancies and oxidation states of sites. Volumetric data such as electron and nuclear densities, Patterson functions, and wavefunctions are displayed as isosurfaces, bird's-eye views and two-dimensional maps. Isosurfaces can be colored according to other physical quantities. Translucent isosurfaces and/or slices can be overlapped with a structural model. Collaboration with external programs enables the user to locate bonds and bond angles in the `graphics area', simulate powder diffraction patterns, and calculate site potentials and Madelung energies. Electron densities determined experimentally are convertible into their Laplacians and electronic energy densities.

4,172 citations

Journal ArticleDOI
TL;DR: A critical review of the synthesis methods for graphene and its derivatives as well as their properties and the advantages of graphene-based composites in applications such as the Li-ion batteries, supercapacitors, fuel cells, photovoltaic devices, photocatalysis, and Raman enhancement are described.
Abstract: Graphene has attracted tremendous research interest in recent years, owing to its exceptional properties. The scaled-up and reliable production of graphene derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO), offers a wide range of possibilities to synthesize graphene-based functional materials for various applications. This critical review presents and discusses the current development of graphene-based composites. After introduction of the synthesis methods for graphene and its derivatives as well as their properties, we focus on the description of various methods to synthesize graphene-based composites, especially those with functional polymers and inorganic nanostructures. Particular emphasis is placed on strategies for the optimization of composite properties. Lastly, the advantages of graphene-based composites in applications such as the Li-ion batteries, supercapacitors, fuel cells, photovoltaic devices, photocatalysis, as well as Raman enhancement are described (279 references).

3,340 citations

Journal ArticleDOI
TL;DR: This work shows that absence of entanglement does not imply classicality, and considers the vanishing of discord as a criterion for the preferred effectively classical states of a system, i.e., the pointer states.
Abstract: Two classically identical expressions for the mutual information generally differ when the systems involved are quantum. This difference defines the quantum discord. It can be used as a measure of the quantumness of correlations. Separability of the density matrix describing a pair of systems does not guarantee vanishing of the discord, thus showing that absence of entanglement does not imply classicality. We relate this to the quantum superposition principle, and consider the vanishing of discord as a criterion for the preferred effectively classical states of a system, i.e., the pointer states.

3,244 citations

Journal ArticleDOI
TL;DR: In this paper, the authors provide a classification of the main problems addressed in the literature with respect to the notion of explanation and the type of black box decision support systems, given a problem definition, a black box type, and a desired explanation, this survey should help the researcher to find the proposals more useful for his own work.
Abstract: In recent years, many accurate decision support systems have been constructed as black boxes, that is as systems that hide their internal logic to the user. This lack of explanation constitutes both a practical and an ethical issue. The literature reports many approaches aimed at overcoming this crucial weakness, sometimes at the cost of sacrificing accuracy for interpretability. The applications in which black box decision systems can be used are various, and each approach is typically developed to provide a solution for a specific problem and, as a consequence, it explicitly or implicitly delineates its own definition of interpretability and explanation. The aim of this article is to provide a classification of the main problems addressed in the literature with respect to the notion of explanation and the type of black box system. Given a problem definition, a black box type, and a desired explanation, this survey should help the researcher to find the proposals more useful for his own work. The proposed classification of approaches to open black box models should also be useful for putting the many research open questions in perspective.

2,805 citations