The year in cardiology: arrhythmias and pacing.

During this last year, there has been much progress with regard to anticoagulant and ablation therapy for atrial fibrillation (AF). Apart from recently issued European Society of Cardiology Guidelines for the management of patients with supraventricular arrhythmias, there has been little progress in research in this field. Ventricular arrhythmias and device therapy have seen modest progress

A Generalized Theory of Varying Alpha

In this paper, we formulate a generalization of the simple Bekenstein-Sandvik-Barrow-Magueijo (BSBM) theory of varying alpha by allowing the coupling constant, \omega, for the corresponding scalar field \psi\ to depend on \psi. We focus on the situation where \omega\ is exponential in \psi\ and find the late-time behaviours that occur in matter-dominated and dark-energy dominated cosmologies. We also consider the situation when the background expansion scale factor of the universe evolves in proportion to an arbitrary power of the cosmic time. We find the conditions under which the fine structure `constant' increases with time, as in the BSBM theory, and establish a cosmic no-hair behaviour for accelerating universes. We also find the conditions under which the fine structure `constant' can decrease with time and compare the whole family of models with astronomical data from quasar absorption spectra.Comment: 25 pages, 6 figures. Minor corrections and clarifications added. Final section on spatial variations removed so that the paper focuses exclusively on time-variatio

Strength and Behavior of Fillet Welded Connections in G450 Sheet Steel

G450 steel to AS 1397 is a cold-reduced sheet steel with in-line galvanizing. Its grade is 65 ksi (450 MPa) yield and 70 ksi (480 MPa) tensile strength. It is widely used in Australia for purlins, and is being used to fabricate light-weight Portal frames, often by welding. The effect of welding on G450 sheet steel in the heat affected zone was unknown and so the project was performed to investigate the strength of fillet welded connections. Transverse and longitudinal fillet welded connections in 0.06 in (1.5 mm) and 0.12 in (3.0 mm) sheet steels were tested to failure. The failure modes and ductility of different types of connections are described. The test results are used to check the design rules in the AISI Specification (Section E2.4) and the Australian/New Zealand Standard for Cold-Formed Steel Structures AS/NZS 4600 (Clause 5.2.3). Recommendations are made for revised capacity factors. The quality of fillet welded connections in thin sheet steels produced by industry fabricators is investigated. The need to complement the macro test with the destructive prying test as part of the pre-qualification procedure for such connections is demonstrated

Strength and Behavior of Flare-bevel and Flare-vee Welded Connections in G450 Sheet Steel

G450 steel to AS 1397 is a cold-reduced sheet steel with in-line galvanizing. Its grade is 65 ksi (450 MPa) yield and 70 ksi (480 MPa) tensile strength. It is widely used in Australia for purlins, and is being used to fabricate light-weight portal frames, often by welding. The effect of welding on G450 sheet steel in the heat affected zone (HAZ) was unknown and so the project was performed to investigate the strength of flare-bevel and flare-vee welded connections. Flare-bevel and flare-vee welded connections in 0.06-in (1.5-mm) and 0.12-in (3.0-mm) sheet steels were tested to failure. The failure modes and ductility of different types of connections are described. The test results are used to check the design rules in the AISI Specification (Section E2.5) and the Australian/New Zealand Standard for Cold-Formed Steel Structures AS/NZS 4600 (Clause 5.2.6). Connections in 0.12-in (3.0-mm) sheet steel failed in the weld and it is important that these connections are checked for weld throat failure, not just parent material failure. The quality of flare-bevel welded connections in thin sheet steels produced by industry fabricators is investigated. The results of this study have recently been incorporated into the AISI Specification for Cold-Formed Steel Structures by reducing the thickness at which weld throat failure should be checked to 2.5 mm (0.10 in)

Spatial Buckling Behavior of High-rise Rack Frames

The paper investigates the global elastic buckling behavior of a high-rise adjustable pallet rack frame composed of thin-walled open sections. It is concluded that the simple element used in many commercial programs for 3D frame analysis is not sufficiently refined for accurate linear buckling analyses of high-rise rack frames

Management of atrial fibrillation

Atrial fibrillation (AF) is a condition of genuine clinical concern. This arrhythmia increases patient morbidity and mortality, most notably due to stroke, thromboembolism and heart failure. Consequentially, there is a strong impetus to acquire a greater understanding of its natural history and course in order to provide crucial evidence-based treatment and resource allocation in the future. The objective of this review article is to present a concise overview of the management of AF, with reference to the recent evidence-based National Institute of Clinical Excellence (NICE) National Clinical Guidelines for the management of AF

Home-based versus hospital-based cardiac rehabilitation after myocardial infarction or revascularisation: design and rationale of the Birmingham Rehabilitation Uptake Maximisation Study (BRUM): a randomised controlled trial

Background: Cardiac rehabilitation following myocardial infarction reduces subsequent mortality, but uptake and adherence to rehabilitation programmes remains poor, particularly among women, the elderly and ethnic minority groups. Evidence of the effectiveness of home-based cardiac rehabilitation remains limited. This trial evaluates the effectiveness and cost-effectiveness of homebased compared to hospital-based cardiac rehabilitation. Methods/design: A pragmatic randomised controlled trial of home-based compared with hospital-based cardiac rehabilitation in four hospitals serving a multi-ethnic inner city population in the United Kingdom was designed. The home programme is nurse-facilitated, manual-based using the Heart Manual. The hospital programmes offer comprehensive cardiac rehabilitation in an outpatient setting. Patients: We will randomise 650 adult, English or Punjabi-speaking patients of low-medium risk following myocardial infarction, coronary angioplasty or coronary artery bypass graft who have been referred for cardiac rehabilitation. Main outcome measures: Serum cholesterol, smoking cessation, blood pressure, Hospital Anxiety and Depression Score, distance walked on Shuttle walk-test measured at 6, 12 and 24 months. Adherence to the programmes will be estimated using patient self-reports of activity