Modal Logics of Topological Relations

Logical formalisms for reasoning about relations between spatial regions play a fundamental role in geographical information systems, spatial and constraint databases, and spatial reasoning in AI. In analogy with Halpern and Shoham's modal logic of time intervals based on the Allen relations, we introduce a family of modal logics equipped with eight modal operators that are interpreted by the Egenhofer-Franzosa (or RCC8) relations between regions in topological spaces such as the real plane. We investigate the expressive power and computational complexity of logics obtained in this way. It turns out that our modal logics have the same expressive power as the two-variable fragment of first-order logic, but are exponentially less succinct. The complexity ranges from (undecidable and) recursively enumerable to highly undecidable, where the recursively enumerable logics are obtained by considering substructures of structures induced by topological spaces. As our undecidability results also capture logics based on the real line, they improve upon undecidability results for interval temporal logics by Halpern and Shoham. We also analyze modal logics based on the five RCC5 relations, with similar results regarding the expressive power, but weaker results regarding the complexity

Parenting ‘gifted and talented’ children in urban areas: Parents' voices

This is the author's accepted manuscript. The final published article is available from the link below. Copyright © 2014 by SAGE Publications.International evidence demonstrates the importance of engaging parents in the education of their ‘high-potential’ children, yet limited research has focused on the involvement of parents from differing economic strata/backgrounds. The current study explored the dilemmas of parenting academically high-ability children from economically deprived urban areas in the UK. Data were gathered from a sample of parents whose children attended a university-based sustained intervention programme for designated ‘gifted’ pupils aged 12–16. Parental perceptions were sought in relation to (a) the usefulness/impact of the intervention programme, (b) parents’ aspirations for their children growing up in economically deprived urban areas and (c) parents’ views on the support provided by the extended family, peer groups and the wider community. The findings have significant implications for both policy and practice and, more specifically, for engaging parents in intervention programmes offered by universities and schools to children in order to increase their access to higher education and for enhancing their life chances

Leeway for the loyal: a model of employee discretion

This article examines the factors underlying task discretion from an economist's perspective. It argues that the key axis for understanding discretion is the trade-off between the positive effects of discretion on potential output per employee and the negative effects of greater leeway on work effort. In empirical analysis using matched employer-employee data, it is shown that discretion is strongly affected by the level of employee commitment. In addition, discretion is generally greater in high-skilled jobs, although not without exceptions, and lower where employees are under-skilled. Homeworking and flexitime policies raise employee discretion. The impact of teamworking is mixed. In about half of cases team members do not jointly decide about work matters, and the net effect of teams on task discretion in these cases is negative. In other cases, where team members do decide matters jointly, the impact is found to be neutral according to employees' perceptions, or positive according to managers' perceptions. There are also significant and substantial unobserved establishment-level factors which affect task discretion

Vector Positronium States in QED3

The homogeneous Bethe-Salpeter equation is solved in the quenched ladder approximation for the vector positronium states of 4-component quantum electrodynamics in 2 space and 1 time dimensions. Fermion propagator input is from a Rainbow approximation Dyson-Schwinger solution, with a broad range of fermion masses considered. This work is an extension of earlier work on the scalar spectrum of the same model. The non-relativistic limit is also considered via the large fermion mass limit. Classification of states via their transformation properties under discrete parity transformations allows analogies to be drawn with the meson spectrum of QCD.Comment: 24 pages, 2 encapsulated postscript figure

Band structure of the Jahn-Teller polaron from Quantum Monte Carlo

A path-integral representation is constructed for the Jahn-Teller polaron (JTP). It leads to a perturbation series that can be summed exactly by the diagrammatic Quantum Monte Carlo technique. The ground-state energy, effective mass, spectrum and density of states of the three-dimensional JTP are calculated with no systematic errors. The band structure of JTP interacting with dispersionless phonons, is found to be similar to that of the Holstein polaron. The mass of JTP increases exponentially with the coupling constant. At small phonon frequencies, the spectrum of JTP is flat at large momenta, which leads to a strongly distorted density of states with a massive peak at the top of the band.Comment: 5 pages of REVTeX, 3 figure

"How do pilates trained physiotherapists utilize and value pilates exercise for MSK conditions? A qualitative study"

Background Pilates is a popular exercise therapy approach offering numerous benefits, including muscular strength, flexibility, control, and core stability. Pilates has been widely utilized in the prevention and rehabilitation of a variety of musculoskeletal disorders. Objectives The aim of this study was to explore the experiences and opinions of Pilates trained NHS and private practice physiotherapists in the UK, regarding the perceived benefits, risks, delivery and rationale for this exercise method. Methods This qualitative study used a self‐designed electronic survey to retrieve the views of 30 physiotherapists, who had undertaken formal Pilates Instruction training, recruited by a purposive and snowball sampling method. Questions were either multiple choice or open‐ended, examined via thematic analysis. Results Physiotherapists identified the most important benefits of Pilates as reduction in fear‐avoidance, improving bodily awareness and increasing muscular strength. Exercises that promote general movement were highlighted as being particularly useful, with a majority recommending daily practice for optimum benefit. Participants recognized lack of core strength as a key indicator, whereas others criticized excessive focus on this principle. Conclusions Physiotherapists identified a range of inter‐linked benefits and recognized that Pilates is hugely modifiable. Individualizing exercises can further encourage participation and negate the restriction of some health conditions. NHS and Private Practice Therapists utilize Pilates in a similar way, although rationales for its use may differ, as the justification for Pilates exercise may be evolving. Pilates appears a valuable methodology in the NHS, which can help patients engage with activity

Employment mobility in high-technology agglomerations: the cases of Oxfordshire and Cambridgeshire

This paper examines labour market behaviour of the highly skilled in high-tech local economies, taking the UK examples of Oxfordshire and Cambridgeshire as case studies. It reports on data from a survey of members of three scientific institutes to compare rates of employee mobility in the two locations and considers the likely explanations and implications of those patterns

On Four-point Functions in the CFT/AdS Correspondence

We discuss the properties of four-point functions in the context of the correspondence between a classical supergravity theory in the bulk of the Anti de Sitter space and quantum conformal field theory at the boundary. The contribution to a four-point function from the exchange of a scalar field of arbitrary mass in AdS space is explicitly identified with that of the corresponding operator in the conformal partial wave expansion of a four-point function on the CFT side. Integral representations are found for the massless vector and graviton exchanges. We also discuss some aspects of the four-point functions of Tr F^2 and Tr F F^* (`dilaton' and `axion') operators in the N =4 supersymmetric Yang-Mills.Comment: 23 pages, using harvmac and epsf, three figures; v2,v3: minor corrections; v4: argument at the end of section 5 corrected and is now consistent with hep-th/9808006 by Freedman et a

Investigating the New Landscapes of Welfare: Housing Policy, Politics and the Emerging Research Agenda

As debates about housing form an increasingly important arena of political controversy, much has been written about the new fissures that have appeared as governments not only struggle to reduce public expenditure deficits but also attempt to address problems such as affordability and homelessness. It is widely anticipated that new conflicts will be played out in the private rental market as access to homeownership becomes unrealistic and the supply of social housing diminishes. However, what other tensions might surface; that hitherto have not been subject to the critical gaze of housing research? In this paper, we provide some thoughts on the nascent policy issues as well as the ideological schisms that are likely to develop in coming years, offering suggestions as to how the focus of housing policy research might be reoriented towards a “politics” framework to capture and better understand the conflicts that are likely to arise

‘Talent-spotting’ or ‘social magic’? Inequality, cultural sorting and constructions of the ideal graduate in elite professions

Graduate outcomes – including rates of employment and earnings – are marked by persistent inequalities related to social class, as well as gender, ethnicity and institution. Despite national policy agendas related to social mobility and ‘fair access to the professions’, high-status occupations are disproportionately composed of those from socially privileged backgrounds, and evidence suggests that in recent decades many professions have become less socially representative. This article makes an original contribution to sociological studies of inequalities in graduate transitions and elite reproduction through a distinct focus on the ‘pre-hiring’ practices of graduate employers. It does this through a critical analysis of the graduate recruitment material of two popular graduate employers. It shows how, despite espousing commitments to diversity and inclusion, constructions of the ‘ideal’ graduate privilege individuals who can mobilise and embody certain valued capitals. Using Bourdieusian concepts of ‘social magic’ and ‘institutional habitus’, the article argues that more attention must be paid to how graduate employers’ practices constitute tacit processes of social exclusion and thus militate against the achievement of more equitable graduate outcomes and fair access to the ‘top jobs