412 research outputs found

    On the application of radio frequency voltages to ion traps via helical resonators

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    Ions confined using a Paul trap require a stable, high voltage and low noise radio frequency (RF) potential. We present a guide for the design and construction of a helical coil resonator for a desired frequency that maximises the quality factor for a set of experimental constraints. We provide an in-depth analysis of the system formed from a shielded helical coil and an ion trap by treating the system as a lumped element model. This allows us to predict the resonant frequency and quality factor in terms of the physical parameters of the resonator and the properties of the ion trap. We also compare theoretical predictions with experimental data for different resonators, and predict the voltage applied to the ion trap as a function of the Q-factor, input power and the properties of the resonant circuit

    The division of labour in South Africa, 1969 - 1977

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    The changing patterns of group politics in Britain

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    Two interpretations of ways in which group politics in Britain have presented challenges to democracy are reviewed: neo-corporatism or pluralistic stagnation and the rise of single issue interest groups. The disappearance of the first paradigm created a political space for the second to emerge. A three-phase model of group activity is developed: a phase centred around production interests, followed by the development of broadly based 'other regarding' groups, succeeded by fragmented, inner directed groups focusing on particular interests. Explanations of the decay of corporatism are reviewed. Single issue group activity has increased as party membership has declined and is facilitated by changes in traditional media and the development of the internet. Such groups can overload the policy-making process and frustrate depoliticisation. Debates about the constitution and governance have largely ignored these issues and there is need for a debate

    A Record of Observations on the Dandelion

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    The positions of primary and secondary schools in the English school field: a case of durable inequality

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    In interviews as part of a research study of structural reform in England, some tension between primary head teachers and their secondary peers was evident. This was symptomatic of a long-standing difference in status between the two phases. At a time when relations between stakeholders in local systems are subject to change, we seek to understand anew why that might be the case and how the tension we found was evidence of a current difference of power within interactions between representatives of the phases. We analyse differences of size, resources, workforce, pedagogy and history, and how they have resulted in different, and differently valued, practices and professional identities. We explore how attributes of the two phases have been counterposed and how, in complex interaction with wider discourses of politics, gender and age, this process has invested the differences with meanings and values that tend to relegate attributes associated with primary school. By focusing on the activation of cumulative inequality in interactions, we contribute a complementary perspective to studies of perceived relative status and highlight the implications for understanding school positioning in local arenas as the role of local authorities is reduced

    Level models of continuing professional development evaluation: a grounded review and critique

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    Continuing professional development (CPD) evaluation in education has been heavily influenced by ‘level models’, deriving from the work of Kirkpatrick and Guskey in particular, which attempt to trace the processes through which CPD interventions achieve outcomes. This paper considers the strengths and limitations of such models, and in particular the degree to which they are able to do justice to the complexity of CPD and its effects. After placing level models within the broader context of debates about CPD evaluation, the paper reports our experience of developing such models heuristically for our own evaluation practice. It then draws on positivist, realist and constructivist traditions to consider some more fundamental ontological and epistemological questions to which they give rise. The paper concludes that level models can be used in a number of ways and with differing emphases, and that choices made about their use will need to reflect both theoretical choices and practical considerations

    Can deliberate efforts to realise aspirations increase capabilities? A South African case study

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    This paper takes up Appadurai's suggestion that aspirations could be used as a key to unlock development for people who are economically marginalised, and that their capabilities could be increased by this approach. The notion of “aspirations” is theoretically and conceptually framed, and then Amartya Sen's use of the term capabilities as the space within which development should be assessed is explored. I subsequently describe a five-year programme in which economically marginalised women in Khayelitsha near Cape Town were assisted in voicing and attempting to realise their aspirations, while being assisted with access to some resources. Capability outcomes and constraints are described and analysed, and the question of adaptive preferences is addressed. I conclude that deliberate efforts to realise aspirations, accompanied by some facilitation, can increase capabilities, but that there are also structural constraints to capability expansion for these women that frustrate their aspiration of class mobility.International Bibliography of Social Science

    Poverty and Well-being in Post-Apartheid South Africa: An Overview of Data, Outcomes and Policy

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    WP 2006-03 January 2006This is an overview of poverty and well-being in the first decade of post-apartheid South Africa. It is an introduction to a volume that brings together some of the most prominent academic research done on this topic for the 10-year review process in South Africa. This overview highlights three key aspects of the picture that the detailed research paints. First, data quality and comparability has been a constant issue in arriving at a consensus among analysts on the outcomes for households and individuals in postapartheid South Africa. Second, while the outcomes on unemployment, poverty and inequality are indeed bad, the outcomes on social indicators and access to public services are much more encouraging. Third, the prospects for rapid and sustained economic growth, without which poverty and well-being cannot be addressed in the long run, are themselves negatively affected by increasing inequality, poverty and unemployment

    Aviation Psychology: Cognition and Personality

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    This study has two main objectives. The first is to measure the personality traits of aviation students at EKU. Recent research indicates the existence of a distinct pilot personality profile, characterized by heightened emotional stability and conscientiousness compared to the general population. The current study will evaluate aviation students at EKU and see how they compare to that specific profile. The second objective is to evaluate aviation students\u27 confidence in their visual abilities during flight and to see whether certain interventions can help them better calibrate their confidence with their actual abilities. Awareness of cognitive limitations is vital for pilots as failure to recognize them can lead to catastrophic consequences. Results will be analyzed to determine the relationship between personality traits, aviation outcomes, and perceptions of visual awareness. Findings from this study could inform aviation instructors, advisors, and others about the role of personality in aviation education and the efficacy of interventions targeting perceptual limitations. This integrated approach aims to enhance aviation training by addressing both individual differences and perceptual challenges encountered in real-world aviation settings
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