359 research outputs found

    A quantitative study of the orientation bias of some edge detector schemes

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    The evaluation of a particular set of edge detection schemes is described. The results obtained are compared with those obtained from an edge detection scheme using a texture oriented approach. The orientational bias of these schemes is emphasized. Improved qualitative observations are reported and a comparison of the evaluation method with another edge detection evaluation method is presented

    Superconductivity from correlated hopping

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    We consider a chain described by a next-nearest-neighbor hopping combined with a nearest-neighbor spin flip. In two dimensions this three-body term arises from a mapping of the three-band Hubbard model for CuO2_2 planes to a generalized tJt-J model and for large O-O hopping favors resonance-valence-bond superconductivity of predominantly dd-wave symmetry. Solving the ground state and low-energy excitations by analytical and numerical methods we find that the chain is a Luther-Emery liquid with correlation exponent Kρ=(2n)2/2K_{\rho} = (2-n)^2/2, where nn is the particle density.Comment: 10 pages, RevTeX 3.0 + 2 PostScript figs. Accepted for publication in Phys.Rev.

    Parenting Styles Are Associated With Overall Child Dietary Quality Within Low-Income and Food-Insecure Households

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    Objective: To examine the association between parenting styles and overall child dietary quality within households that are low-income and food-insecure. Design: Child dietary intake was measured via a 24 h dietary recall. Dietary quality was assessed using the Healthy Eating Index-2005 (HEI-2005). Parenting styles were measured and scored using the Parenting Styles and Dimensions Questionnaire. Linear regressions were used to test main and interaction associations between HEI-2005 scores and parenting styles. Setting: Non-probability sample of low-income and food-insecure households in South Carolina, USA. Participants: Parent–child dyads (n 171). Parents were ≥18 years old and children were 9–15 years old. Results: We found a significant interaction between authoritative and authoritarian parenting style scores. For those with a mean authoritarian score, each unit increase in authoritative score was associated with a higher HEI-2005 score (b = 3·36, P \u3c 0.05). For those with an authoritarian score that was 1 SD above the mean authoritarian score, each unit increase in authoritative score was associated with a higher HEI-2005 score (b = 8.42, P \u3c 0.01). For those with an authoritarian score that was −1 SD below the mean authoritarian score, each unit increase in authoritative score was associated with a lower HEI-2005 score; however, this was not significant (b = −1·69, P \u3e 0·05). Permissive parenting style scores were negatively associated with child dietary quality (b = −2·79, P \u3c 0·05). Conclusions: Parenting styles should be considered an important variable that is associated with overall dietary quality in children living within low-income and food-insecure households

    Managing lifestyle change to reduce coronary risk: a synthesis of qualitative research on peoples’ experiences

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    Background Coronary heart disease is an incurable condition. The only approach known to slow its progression is healthy lifestyle change and concordance with cardio-protective medicines. Few people fully succeed in these daily activities so potential health improvements are not fully realised. Little is known about peoples’ experiences of managing lifestyle change. The aim of this study was to synthesise qualitative research to explain how participants make lifestyle change after a cardiac event and explore this within the wider illness experience. Methods A qualitative synthesis was conducted drawing upon the principles of meta-ethnography. Qualitative studies were identified through a systematic search of 7 databases using explicit criteria. Key concepts were identified and translated across studies. Findings were discussed and diagrammed during a series of audiotaped meetings. Results The final synthesis is grounded in findings from 27 studies, with over 500 participants (56% male) across 8 countries. All participants experienced a change in their self-identity from what was ‘familiar’ to ‘unfamiliar’. The transition process involved ‘finding new limits and a life worth living’ , ‘finding support for self’ and ‘finding a new normal’. Analyses of these concepts led to the generation of a third order construct, namely an ongoing process of ‘reassessing past, present and future lives’ as participants considered their changed identity. Participants experienced a strong urge to get back to ‘normal’. Support from family and friends could enable or constrain life change and lifestyle changes. Lifestyle change was but one small part of a wider ‘life’ change that occurred. Conclusions The final synthesis presents an interpretation, not evident in the primary studies, of a person-centred model to explain how lifestyle change is situated within ‘wider’ life changes. The magnitude of individual responses to a changed health status varied. Participants experienced distress as their notion of self identity shifted and emotions that reflected the various stages of the grief process were evident in participants’ accounts. The process of self-managing lifestyle took place through experiential learning; the level of engagement with lifestyle change reflected an individual’s unique view of the balance needed to manage ‘realistic change’ whilst leading to a life that was perceived as ‘worth living’. Findings highlight the importance of providing person centred care that aligns with both psychological and physical dimensions of recovery which are inextricably linked

    Theorising variation in engagement in professional and curriculum development: performativity, capital, systems and purpose

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    Increasingly, policymakers seek to improve the quality of teaching through curriculum innovations and continuing professional development (CPD) programmes. However, engagement by schools and teachers varies due to mediating influences of neoliberal policies. In this article, we contribute to understanding how these tendencies affect participation. Problematising the notion of context, we examine ways in which systemic influences interacted with participation in a government-funded mathematics professional and curriculum development programme and also with participants’ purposes. A 3-level clustered Randomised Controlled Trial (RCT) and an implementation and process evaluation were augmented by in-depth case studies, cross-case analysis and the application of theoretical constructs to interpret findings. Theories of capital, figured worlds and systemic coupling are utilised to theorise context. Different levels of engagement are partly explainable by: the interaction of schools' relative systemic advantage and disadvantage; their orientation and coupling to performativity regimes; and the alignment or dissonance between continuing professional development or change programmes and the pedagogical and CPD cultures and purposes of the ‘actors’ (schools, departments and teachers). Performativity concerns restricted what were considered legitimate outcomes in some case study schools. This depended on teachers and schools' positioning in terms of relative degrees of systemic privilege or disadvantage - understood as economic, cultural, social and symbolic capital - and also in terms of figured worlds and system coupling. The case studies provide insights into how collaborative professional learning can be fostered more productively. Methodologically, we demonstrate the power of combining methodologies and applying explanatory social theory to augment quasi-experimental paradigms

    What young people report about the personal characteristics needed for social science research after carrying out their own investigations in an after-school club

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    Several arguments have been put forward about the benefits of young people carrying out their own social science research in terms of empowering their voices and their participation. Much less attention has been paid to investigating the understandings young people develop about the research process itself. Seven twelve-year-olds carried out self-directed social science research into a topic of their choice. Towards the end of their six months experience we used a questionnaire and follow-up semi-structured interviews to investigate, from a socio-cultural perspective, what the young people thought about being a researcher. Thematic analysis of the interviews identified three themes and eight subthemes suggesting that they were aware of: the need to demonstrate researcher/research integrity (be thorough, truthful, orderly, and have a good understanding of research process); the need for good interpersonal skills and standards; and good self-management skills (be resilient, agentic, committed, and good at time management). We discuss how first-hand social science research experience might: be relevant to several areas of schooling; give young people experience of the personal characteristics important for success; help young people to realise that they can be social science researchers, and offer advanced and novel learning experiences outside the constraints of the school curriculum
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