156 resultados para Choice correspondences


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According to the axiomatic literature on consensus methods, the best collective choice by one method of preference aggregation can easily be the worst by another. Are award committees, electorates, managers, online retailers, and web-based recommender systems stuck with an impossibility of rational preference aggregation? We investigate this social choice conundrum for seven social choice methods: Condorcet, Borda, Plurality, Antiplurality, the Single Transferable Vote, Coombs, and Plurality Runoff. We rely on Monte Carlo simulations for theoretical results and on twelve ballot datasets from American Psychological Association (APA) presidential elections for empirical results. Each of these elections provides partial rankings of five candidates from about 13,000 to about 20,000 voters. APA preferences are neither domain-restricted nor generated by an Impartial Culture. We find virtually no trace of a Condorcet paradox. In direct contrast with the classical social choice conundrum, competing consensus methods agree remarkably well, especially on the overall best and worst options. The agreement is also robust under perturbations of the preference prole via resampling, even in relatively small pseudosamples. We also explore prescriptive implications of our findings.

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Self-determination and decision-making are acknowledged internationally as key rights of persons with disabilities and should play an important role in the development of educational plans and procedures. Not only is the chance for individuals with developmental disabilities to select their own tasks, leisure activities or reinforcers a valuable way of enhancing rights-based education and personal dignity, but choice-making opportunities may also function as a useful clinical or educational tool if they actually improve the efficacy of programmes aimed at the acquisition of socially relevant behaviours and life skills or the reduction of challenging behaviours.

The study reported here assessed whether or not choice affected effectiveness of an educational procedure for three children on the autism spectrum. Following a preference assessment, a number of discrete teaching trials were conducted with each child and, contingent upon targeted responses, either the child or the therapist selected one of three preferred reinforcer items. Reinforcer choice did not affect intervention effectiveness for two of the children; however, performance and motivation improved for the third child. Results re-affirmed the importance of thorough preference assessments prior to intervention and showed that additional stimulus choice contingent on the target response may improve motivation and outcomes for some children.

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Using rewards may be an effective method to positively influence adolescent eating behaviour, but evidence regarding this approach is limited. The aim of this study was to explore young adolescent views about a proposed reward intervention associated with food choice in school canteens. Focus groups were held in 10 schools located in lower socioeconomic areas within Northern Ireland and involved 90 pupils aged 11-12 years (54 girls, 36 boys). Our findings indicated a high degree of acceptability for a reward scheme but there was major diversity in the type of rewards valued by pupils, largely defined by geographical area and socio-cultural differences. Pupils from rural areas tended to emphasize group-based and longer-term rewards, whereas pupils from urban-city schools tended to suggest individualistic and immediate rewards. The major factors influencing food choice were food price, value for money, taste and visual appearance. Pupils felt that factors outside of their control, such as being assigned to the second lunch sitting placed considerable constraints on their food choice. This research not only indicated a high degree of acceptability for a rewards-based intervention but also highlighted a number of socio-cultural and environmental factors that should be considered by researchers when developing such an intervention.

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The A-level Mathematics qualification is based on a compulsory set of pure maths modules and a selection of applied maths modules. The flexibility in choice of applied modules has led to concerns that many students would proceed to study engineering at university with little background in mechanics. A survey of aerospace and mechanical engineering students in our university revealed that a combination of mechanics and statistics (the basic module in both) was by far the most popular choice of optional modules in A-level Mathematics, meaning that only about one-quarter of the class had studied mechanics beyond the basic module within school mathematics. Investigation of student performance in two core, first-year engineering courses, which build on a mechanics foundation, indicated that any benefits for students who studied the extra mechanics at school were small. These results give concern about the depth of understanding in mechanics gained during A-level Mathematics.

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This chapter examines the issue of coexistence of genetically modified organisms (GMOs) alongside conventional and organic crops. The central focus is on whether there is a veritable opportunity for coexistence of all three types of crops, which allows for freedom of choice by both farmers and consumers. It commences by considering the nature of the general GM regime, the relationship between the frameworks for cultivation and the use and sale of GM food and feed, and the main elements of the cultivation regime. In light of this, the concept of coexistence is considered, with an evaluation of both the legal and practical elements. Although the general GM regime is controlled at an EU level, coexistence is apparently left to the Member States who may take appropriate coexistence measures. Nonetheless, the Commission has created Recommendations that are to guide the Member States in their choice of measures. To a great extent, what is considered ‘appropriate’ is to be determined by the economic impact upon the farmers and the relationship with the labelling thresholds. The chapter evaluates the future of coexistence, bearing in mind the continued use of the safeguard clauses, the declaration of ‘GM-free’ regions, the potential for national ‘opt-outs’ and the general practical challenges of maintaining coexistence including the ‘domino effect’. Overall, it is arguable that coexistence is a misnomer and that if the term’s meaning is strictly maintained then veritable coexistence that allows for freedom of choice by both farmers and consumers seems unattainable. Although not directly controlled by CAP, there are strong areas of overlap and they share a number of similar objectives; the chapter will conclude by considering whether the approaches in relation to CAP and the cultivation of GMOs are converging or diverging.

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Traditionally, undergraduate students in University College Cork (UCC) have been taught to use amalgam as the first choice material for direct restoration of posterior cavities. Since 2005 the use of composite resins has replaced amalgam as the first choice material. An audit was conducted of all direct restorations placed by final year students from UCC from 2004 until 2009. Results showed that over a six year period, final year UCC dental undergraduate students placed proportionately more direct composite resin restorations and significantly fewer amalgam restorations. The need for and undergraduate exposure to, provision of amalgam restorations may have to be revisited.

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Consociational institutional arrangements in deeply divided societies are often criticised for cementing the underlying conflict cleavage, encouraging the continued dominance of conflict-based party competition and voter behaviour and prohibiting the emergence of 'normal' (that is, non-conflict-based) dimensions of political competition. However, drawing on evidence from a post-election survey at the 2009 Northern Ireland election to the European Parliament, I find that EU issues determined intra-bloc vote choice (at least in the nationalist community). This suggests that there is potential for regional integration projects, such as the EU, to contribute to the normalisation of politics in a consociational system by acting as the source of an externally generated dimension of political competition. © 2012 Macmillan Publishers Ltd.