Towards a non-local density functiona description of exchange and correlation

Kohn-Sham density functional theory (DFT) is a popular method used to investigate the properties of matter. Although exact in principle, DFT is in practice limited by a single approximation for the exchange-correlation functional - the quantity that describes the many-body interactions between electrons. This thesis is concerned with developing improved exchange-correlation functionals for use in practical DFT calculations. The standard functional currently used in solid state physics, and also popular in quantum chemistry, is the generalised gradient approximation (GGA), which requires only the local density, n(r), and the density gradient, ∆n(r), as input. A flexible semi-empirical GGA form, containing 15 free parameters that are fitted to near-exact molecular data is implemented within the plane-wave pseudopotential (PW-PP) Kohn-Sham scheme, to assess the possibility of employing semi-empirical GGAs in solid state applications. Self-consistent calculations performed for several bulk semiconductor properties using this GGA reveal that, overall, no improvement is attained over a conventional non-empirical GGA used in solid state physics. The remainder of the thesis focuses on a fully non-local functional known as the weighted density approximation (WDA), which utilises the global density of a system, n(r'), as input. An efficient computational algorithm is devised for use within the PW-PP formalism which enables fully self-consistent WDA calculations to be performed. Physical properties are shown to be intimately related to the particular form used for the pair-correlation function, Gwda/xc(r,r'), and by comparing with recent variational Monte Carlo (VMC) data, it is shown that the forms that provide a good description of exchange-correlation holes, nxc(r,r'), also lead to the most accurate bulk properties. For strongly inhomogeneous electron gas systems, the WDA provides close agreement with the VMC method for a variety of exchange-correlation quantities. The success of the fully non-local approach given by the WDA for other model electron gas systems studied suggests that the WDA is a very promising functional

Arson, Treason and Plot: Britain, America and the Law, 1770-1777

The problems of arson, treason and national security became entangled in the politics of Britain and its Atlantic empire between 1770 and 1777. Fears of French military terrorism were compounded by the increasingly violent resistance of the American colonies. Two dockyard fires in Portsmouth, in 1770 and 1777, and the attack on, and burning of, the royal navy ship Gaspee off Rhode Island in 1772, provoked both legal and political difficulties for the British government. New laws on arson and treason were passed yet proved almost impossible to implement in full outside England

J.M. Beattie, Policing and Punishment in London, 1660-1750: Urban Crime and the Limits of Terror

With this book, John Beattie moves geographically and symbolically from the suburban fringes which were the focus of his earlier work to the centre of both London and English crime. By a thorough analysis of London’s and Middlesex’s trials at the Old Bailey from the Restoration to 1750, he reflects profoundly on three aspects of crime in early modern English society – the nature of the criminals before the London courts, the responses to crimes by the city’s judicial authorities, and the role..

J.M. Beattie, Policing and Punishment in London, 1660-1750: Urban Crime and the Limits of Terror

With this book, John Beattie moves geographically and symbolically from the suburban fringes which were the focus of his earlier work to the centre of both London and English crime. By a thorough analysis of London’s and Middlesex’s trials at the Old Bailey from the Restoration to 1750, he reflects profoundly on three aspects of crime in early modern English society – the nature of the criminals before the London courts, the responses to crimes by the city’s judicial authorities, and the role..

Running away and returning home: the fate of English convicts in the American colonies

The myth of return – that many English criminals transported to the American colonies ran away and returned home – dominated eighteenth-century views of the punishment. In both criminal biographies and political discussion this was widely believed. Yet data from both sides of the Atlantic suggest that few in fact returned successfully. The systems of surveillance in the colonies, designed to detect and recapture escaping slaves, servants and convicts, were effective. Also, the difficulties they faced in trying to return were for many convicts, particularly women, insuperable. This article analyses the fates of convicts from the north and west of England, their patterns of running away, and the characters of those few who managed to return.Le mythe du retour – selon lequel de nombreux criminels anglais déportés vers les colonies américaines s’échappaient et retournaient chez eux – dominait dans les représentations de la peine au XVIIIe siècle. Cette croyance était largement partagée dans les biographies des criminels et des débats politiques. Pourtant, les données issues des deux rives de l’Atlantique suggèrent que ces retours étaient peu fréquents. Les systèmes de surveillance des colonies, conçus pour détecter et reprendre les esclaves, les serviteurs et les bagnards, étaient efficaces. En outre, les difficultés qu’affrontaient les fuyards pour revenir étaient insurmontables pour beaucoup d’entre eux, en particulier les femmes. Cet article analyse les destinées des bagnards du nord et de l’ouest de l’Angleterre, la manière dont ils s’enfuyaient et les caractéristiques de ceux, peu nombreux, qui parvenaient à revenir

Development of an optimised 1:1 physiotherapy intervention post first-time lumbar discectomy:a mixed-methods study

Objectives To develop an optimised 1:1 physiotherapy intervention that reflects best practice, with flexibility to tailor management to individual patients, thereby ensuring patient-centred practice. Design Mixed-methods combining evidence synthesis, expert review and focus groups. Setting Secondary care involving 5 UK specialist spinal centres. Participants A purposive panel of clinical experts from the 5 spinal centres, comprising spinal surgeons, inpatient and outpatient physiotherapists, provided expert review of the draft intervention. Purposive samples of patients (n=10) and physiotherapists (n=10) (inpatient/outpatient physiotherapists managing patients with lumbar discectomy) were invited to participate in the focus groups at 1 spinal centre. Methods A draft intervention developed from 2 systematic reviews; a survey of current practice and research related to stratified care was circulated to the panel of clinical experts. Lead physiotherapists collaborated with physiotherapy and surgeon colleagues to provide feedback that informed the intervention presented at 2 focus groups investigating acceptability to patients and physiotherapists. The focus groups were facilitated by an experienced facilitator, recorded in written and tape-recorded forms by an observer. Tape recordings were transcribed verbatim. Data analysis, conducted by 2 independent researchers, employed an iterative and constant comparative process of (1) initial descriptive coding to identify categories and subsequent themes, and (2) deeper, interpretive coding and thematic analysis enabling concepts to emerge and overarching pattern codes to be identified. Results The intervention reflected best available evidence and provided flexibility to ensure patient-centred care. The intervention comprised up to 8 sessions of 1:1 physiotherapy over 8 weeks, starting 4 weeks postsurgery. The intervention was acceptable to patients and physiotherapists. Conclusions A rigorous process informed an optimised 1:1 physiotherapy intervention post-lumbar discectomy that reflects best practice. The developed intervention was agreed on by the 5 spinal centres for implementation in a randomised controlled trial to evaluate its effectiveness