An Exponential Lower Bound for the Latest Deterministic Strategy Iteration Algorithms

This paper presents a new exponential lower bound for the two most popular deterministic variants of the strategy improvement algorithms for solving parity, mean payoff, discounted payoff and simple stochastic games. The first variant improves every node in each step maximizing the current valuation locally, whereas the second variant computes the globally optimal improvement in each step. We outline families of games on which both variants require exponentially many strategy iterations

The practitioner perspective on the modeling of pedagogy and practice

The promotion of e-learning in policies internationally has led to questions about how best to employ technology in support of learning. A range of models has since been developed that attempts to relate pedagogy to technology. However, research into the effectiveness of such models in changing teaching practice is sparse, and work that compares these models to practitioners’ own representations of their practice is absent. The study described here involved asking practitioners to model their own practice, and to compare these with a model developed by a government organisation. Practitioners were adept at using existing models and repurposing them to suit their own context. Our research provided evidence of broad acceptance of the existing model with practitioners, but indicated that practitioners would take this tool and remodel it for their own contexts of learning to make it meaningful, relevant and useful to them

Toroidal automorphic forms, Waldspurger periods and double Dirichlet series

The space of toroidal automorphic forms was introduced by Zagier in the 1970s: a GL_2-automorphic form is toroidal if it has vanishing constant Fourier coefficients along all embedded non-split tori. The interest in this space stems (amongst others) from the fact that an Eisenstein series of weight s is toroidal for a given torus precisely if s is a non-trivial zero of the zeta function of the quadratic field corresponding to the torus. In this paper, we study the structure of the space of toroidal automorphic forms for an arbitrary number field F. We prove that it decomposes into a space spanned by all derivatives up to order n-1 of an Eisenstein series of weight s and class group character omega precisely if s is a zero of order n of the L-series corresponding to omega at s, and a space consisting of exactly those cusp forms the central value of whose L-series is zero. The proofs are based on an identity of Hecke for toroidal integrals of Eisenstein series and a result of Waldspurger about toroidal integrals of cusp forms combined with non-vanishing results for twists of L-series proven by the method of double Dirichlet series.Comment: 14 page

Arthroscopic washout of the knee: a procedure in decline.

BACKGROUND: Osteoarthritis (OA) of the knee is a chronic, progressive condition which often requires surgical intervention. The evidence for the benefits of arthroscopic debridement or washout for knee OA is weak and arthroscopy is currently only indicated in the UK if there is a history of mechanical locking of the knee. OBJECTIVES: To investigate whether there has been any change in the number of arthroscopies performed in the UK since the 2007 NICE guidance on knee arthroscopy and the 2008 Cochrane review of arthroscopic debridement for OA of the knee. METHODS: We interrogated data from the Hospital Episodes Statistics (HES) database with Office of Population Censuses and Surveys-4 (OPSC-4) codes pertaining to therapeutic endoscopic operations in the 60-74 year old and 75 and over age groups. RESULTS: The number of arthroscopic knee interventions in the UK decreased overall from 2000 to 2012, with arthroscopic irrigations decreasing the most by 39.6 per 100,000 population (80%). However, the number of arthroscopic meniscal resections increased by 105.3 per 100,000 (230%) population. These trends were mirrored in both the 60-74 and 75 and over age groups. CONCLUSIONS: Knee arthroscopy in the 60-74 and 75 and over age groups appears to be decreasing but there is still a large and increasing number of arthroscopic meniscal resections being performed

Teaching staff knowledge, attributions and confidence in relation to working with children with an intellectual disability and challenging behaviour

The present study examined Scottish teaching staff knowledge about the definition and management of challenging behaviour displayed by children with an intellectual disability. Knowledge levels were relatively low, and participants were most likely to define challenging behaviour by function or topography. Teaching staff were largely unaware of positive programming strategies, suggesting that they may not be properly equipped to manage challenging behaviour effectively in the longer term. The teaching staff were found to hold attributions which research suggests are associated with reduced helping behaviour and increased anger. This indicates a continuing need to identify effective ways of promoting more accurate knowledge and positive attributions in teaching staff

Needs or rights? A challenge to the discourse of special education

It is nearly 30 years since Mary Warnock's Report of the Committee of Enquiry into the Education of Handicapped Children and Young People introduced the phrase ‘special educational needs’ into the UK education system. In this article, Katherine Runswick-Cole, Research Associate at Manchester Metropolitan University, and Nick Hodge, Principal Lecturer in Research Development at Sheffield Hallam University, argue for the abandonment of the ‘special needs’ discourse, claiming that it has, in fact, led to exclusionary practices within education. Building on the work of early years educators in Reggio Emilia schools in Northern Italy, the authors advocate for the adoption of the phrase ‘educational rights’ and suggest that the positive impact of such a linguistic turn would be significant for the lives of young people currently described as having ‘special educational needs’ and for children's rights

Real-time dynamics of the formation of hydrated electrons upon irradiation of water clusters with extreme ultraviolet light

Free electrons in a polar liquid can form a bound state via interaction with the molecular environment. This so-called hydrated electron state in water is of fundamental importance e.g.~in cellular biology or radiation chemistry. Hydrated electrons are highly reactive radicals that can either directly interact with DNA or enzymes, or form highly excited hydrogen (H∗) after being captured by protons. Here, we investigate the formation of the hydrated electron in real-time employing XUV femtosecond pulses from a free electron laser, in this way observing the initial steps of the hydration process. Using time-resolved photoelectron spectroscopy we find formation timescales in the low picosecond range and resolve the prominent dynamics of forming excited hydrogen states

Educating Health Professionals about Disability: A Review of Interventions

Health professionals need to understand the human rights and health needs of disabled people. This review of evidence on interventions demonstrates that a range of often innovative approaches have been trialled. Lectures by faculty are less effective in changing attitudes than contact with disabled people themselves. Existing examples of good practice need to be scaled up, and better and more long-term evaluations of impact are required

Synthesizing diverse evidence: the use of primary qualitative data analysis methods and logic models in public health reviews

Objectives: The nature of public health evidence presents challenges for conventional systematic review processes, with increasing recognition of the need to include a broader range of work including observational studies and qualitative research, yet with methods to combine diverse sources remaining underdeveloped. The objective of this paper is to report the application of a new approach for review of evidence in the public health sphere. The method enables a diverse range of evidence types to be synthesized in order to examine potential relationships between a public health environment and outcomes. Study design: The study drew on previous work by the National Institute for Health and Clinical Excellence on conceptual frameworks. It applied and further extended this work to the synthesis of evidence relating to one particular public health area: the enhancement of employee mental well-being in the workplace. Methods: The approach utilized thematic analysis techniques from primary research, together with conceptual modelling, to explore potential relationships between factors and outcomes. Results: The method enabled a logic framework to be built from a diverse document set that illustrates how elements and associations between elements may impact on the well-being of employees. Conclusions: Whilst recognizing potential criticisms of the approach, it is suggested that logic models can be a useful way of examining the complexity of relationships between factors and outcomes in public health, and of highlighting potential areas for interventions and further research. The use of techniques from primary qualitative research may also be helpful in synthesizing diverse document types. (C) 2010 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved