6,081 research outputs found

    Contexts of learning in schools

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    The research reported in this the pie has been an attempt to investigate and describe some of the realities of classroom learning. Beginning with a critical review of previous research in the sociology of education the first chapter goes on to report the author's initial attempt at research in this field. The conclusions were that, (i) social class factors are mediated through classroom processes, (ii) the expectations of the teacher are a likely influence on pupil achievement, and (iii) the attitudes of a child towards school learning are effectively determined by his experiences at primary school. Chapter two describes an experiment supporting the hypothesis that children are aware of their teacher's expectations for them. A repertory grid technique for determining the perceptions of a teacher towards individual pupils is explained in chapter three. This chapter also presents an analysis of pupils' classrcom behaviour in terms of the constructs of those pupils' teacher. Chapter four looks at the power of these constructs to account for achievement when compared with a socio-economic variable. It is argued that social class is net a significant factor at classroom level. In chapter five a research plan is outlined. This involved observing pupils in five primary schools and following them to a single comprehensive school. This chapter argues that the symbolic interectionism of C-.H. Mead provides a useful theoretical framework for explaining classroom interactions between teacher and pupil. Chapter six is an empirical account of the curriculum and teaching methods in the observed schools. Chapter seven presents four case studies in which it is shown how children transact through these interaction? an agreed classroom-self. By the repertory grid technique it was? possible to shew which pupils were perceived favourably and which unfavourably by their teachers'. Chapter eight discusses children 'who were perceived differently by teachers in primary and secondary school. The adaptation made by these children to their new school was related to their teachers perceptions of then, Chapter nine deals with, academic ability and self perception. An experiment showing the wide agreement between the members of a class about their relative abilities is described. Chapter ten is an account cf the formation of. friendship cliques in the non-streamed primary and secondary schools I observed. Finally, chapter eleven argues the relevance of my findings to educational research

    Cold-formed steel channel sections under end-two-flange loading condition:design for edge-stiffened holes, unstiffened holes and plain webs

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    In cold-formed steel (CFS) channel sections, web holes are becoming increasingly popular. Such holes, however, result in the sections becoming more susceptible to web crippling, especially under concentrated loads applied near the web holes. Traditional web holes are normally punched or bored and are unstiffened. Recently, a new generation of CFS channel sections with edge-stiffened web holes has been developed by the CFS industry and is being widely used. However, no research is available in the literature which investigated the web crippling strength of CFS channel sections with edge-stiffened circular web holes under the end-two-flange (ETF) loading conditions. A combination of experimental tests and non-linear FEA were used to investigate the effect of such stiffened holes on web crippling behaviour under ETF loading conditions. The results of 30 web crippling tests are presented. Non-linear FE models are described, and the results are compared against the laboratory test results; a good agreement was obtained in terms of both the strength and failure modes. The results indicate that the stiffened holes can significantly improve the web crippling strength of CFS channel sections. A parametric study involving 1116 FEA was then performed, covering the effect of different hole sizes, edge-stiffener lengths and fillet radii, length of the bearing plates and position of holes in the web. Finally, design recommendations in the form of web crippling strength reduction factors are proposed, that are conservative to both the experimental and FE results

    Effects of edge-stiffened web openings on the behaviour of cold-formed steel channel sections under compression

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    The use of cold-formed steel (CFS) channel sections are becoming popular as the load-carrying members in building structures, and such channel sections often include web openings for the ease of installation of services. Traditional web openings are normally punched, and are unstiffened which can restrict the size and spacing of web openings. Recently, a new generation of CFS channel sections with edge-stiffened web openings has been developed, and is widely used in New Zealand. However, no experimental investigation has been reported in the literature for such channel sections under compression. In this paper, a total of 75 results comprising 26 axial compression tests and 49 finite element analysis results are reported on the compression resistance of CFS channel sections with both edge-stiffened and unstiffened web openings. For comparison, channel sections without web openings were also tested. For all specimens, initial imperfections were measured using a laser scanner. A nonlinear elasto-plastic finite element model was also developed, and the results showed good agreement with the test results. A parametric study was conducted using the validated finite element model to investigate the effect of opening spacing and column length on compression resistance of channel sections. It is shown that for the case of a channel section having seven edge-stiffened web openings, the compression resistance increased by as much as 22%, compared to a plain channel section. For comparison, the same section having unstiffened web openings had a 20% reduction in compression resistance, compared to a plain channel section

    Web crippling behaviour of cold-formed steel channel sections with edge-stiffened and unstiffened circular holes under interior-two-flange loading condition

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    Recently, a new generation of cold-formed steel (CFS) channel sections with edge-stiffened circular holes have been developed by industry in New Zealand. No previous research, however, has considered the web crippling strength of CFS channel sections with edge-stiffened circular web holes under the interior-two-flange (ITF) loading conditions. In this paper, a combination of experimental investigation and non-linear finite element analysis (FEA) are used to investigate the effect of edge-stiffened holes under ITF loading conditions;for comparison, channel sections without holes and with unstiffened holes are also considered. In total, 30 web crippling test results are reported. A non-linear finite element (FE) model is described, and the results were compared against the test results, which showed a good agreement in terms of both the web crippling strength and failure modes. The results indicate that the stiffened web holes can significantly improve the web crippling strength of CFS channel sections. Using the validated FE model, a parametric study was conducted which include 1116 FE analyses, covering the effect of different hole sizes, edge-stiffener lengths and fillet radii, length of the bearing plates and position of the holes in the web. From the results of the parametric study, design recommendations in the form of web crippling strength reduction factors are proposed, that are conservative to both the experimental and FE results

    Reviews

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    The following publications have been reviewed by the mentioned authors;Welsh Crafts by Mary Eirwen Jones, reviewed by Roy NashA Source Book of Picture Making by Henry Pluckrose, reviewed by R. HartApproaches to Drawing by Leo Walmsley, reviewed by John EgglestonMoulded and Slip Cast Pottery and Ceramics by David Cowley, reviewed by Michael PaffardPainting by John Lancaster, reviewed by R. N. MacGregorDesign Resource Sheets by R. N. Billington and J. R. Jeffrey, reviewed by Dick SuttonEnamelling on Metal, Oppi. Intracht, reviewed by J. N. AtkinsProcesses by Jack Bainbridge, reviewed by Michael SayerArtists and People by Su Braden, reviewed by Roy ShawMake Your Own Musical Instrument by Stuart Dalby, reviewed by Eric DecorteDesign in General Education by John Harahan, reviewed by Bernard AylwardPainting Without a Brush by Roy Sparkes, reviewed by John LancasterBuilding Craft Equipment by A. Jay and Carol W. Abrams, reviewed by S. R. BlundellPyrography by Berhand Havez and Jean-Claude Varlet, reviewed by Paul Kin

    Percolation model for structural phase transitions in Li1−x_{1-x}Hx_xIO3_3 mixed crystals

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    A percolation model is proposed to explain the structural phase transitions found in Li1−x_{1-x}Hx_xIO3_3 mixed crystals as a function of the concentration parameter xx. The percolation thresholds are obtained from Monte Carlo simulations on the specific lattices occupied by lithium atoms and hydrogen bonds. The theoretical results strongly suggest that percolating lithium vacancies and hydrogen bonds are indeed responsible for the solid solution observed in the experimental range 0.22<x<0.360.22 < x < 0.36.Comment: 4 pages, 2 figure

    Evolution of miRNA-binding sites and regulatory networks in cichlids

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    The divergence of regulatory regions and gene regulatory network (GRN) rewiring is a key driver of cichlid phenotypic diversity. However, the contribution of miRNA-binding site turnover has yet to be linked to GRN evolution across cichlids. Here, we extend our previous studies by analyzing the selective constraints driving evolution of miRNA and transcription factor (TF)-binding sites of target genes, to infer instances of cichlid GRN rewiring associated with regulatory binding site turnover. Comparative analyses identified increased species-specific networks that are functionally associated to traits of cichlid phenotypic diversity. The evolutionary rewiring is associated with differential models of miRNA- and TF-binding site turnover, driven by a high proportion of fast-evolving polymorphic sites in adaptive trait genes compared with subsets of random genes. Positive selection acting upon discrete mutations in these regulatory regions is likely to be an important mechanism in rewiring GRNs in rapidly radiating cichlids. Regulatory variants of functionally associated miRNA- and TF-binding sites of visual opsin genes differentially segregate according to phylogeny and ecology of Lake Malawi species, identifying both rewired, for example, clade-specific and conserved network motifs of adaptive trait associated GRNs. Our approach revealed several novel candidate regulators, regulatory regions, and three-node motifs across cichlid genomes with previously reported associations to known adaptive evolutionary traits

    Racial disparities in the SOFA score among patients hospitalized with COVID-19

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    BACKGROUND: Sequential Organ Failure Assessment (SOFA) score predicts probability of in-hospital mortality. Many crisis standards of care suggest the use of SOFA scores to allocate medical resources during the COVID-19 pandemic. RESEARCH QUESTION: Are SOFA scores elevated among Non-Hispanic Black and Hispanic patients hospitalized with COVID-19, compared to Non-Hispanic White patients? STUDY DESIGN AND METHODS: Retrospective cohort study conducted in Yale New Haven Health System, including 5 hospitals with total of 2681 beds. Study population drawn from consecutive patients aged ≥18 admitted with COVID-19 from March 29th to August 1st, 2020. Patients excluded from the analysis if not their first admission with COVID-19, if they did not have SOFA score recorded within 24 hours of admission, if race and ethnicity data were not Non-Hispanic Black, Non-Hispanic White, or Hispanic, or if they had other missing data. The primary outcome was SOFA score, with peak score within 24 hours of admission dichotomized as \u3c6 or ≥6. RESULTS: Of 2982 patients admitted with COVID-19, 2320 met inclusion criteria and were analyzed, of whom 1058 (45.6%) were Non-Hispanic White, 645 (27.8%) were Hispanic, and 617 (26.6%) were Non-Hispanic Black. Median age was 65.0 and 1226 (52.8%) were female. In univariate logistic screen and in full multivariate model, Non-Hispanic Black patients but not Hispanic patients had greater odds of an elevated SOFA score ≥6 when compared to Non-Hispanic White patients (OR 1.49, 95%CI 1.11-1.99). INTERPRETATION: Given current unequal patterns in social determinants of health, US crisis standards of care utilizing the SOFA score to allocate medical resources would be more likely to deny these resources to Non-Hispanic Black patients

    Surface plasmons on zig-zag gratings

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    publication-status: Publishedtypes: ArticleThis paper was published in Optics Express and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.20.023921 Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.© Copyright 2012 Optical Society of Americ

    The Explosive Combination of Religious Decentralisation and Autocracy: the Case of Islam

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    The relationship between religion and politics is explored from a theoretical standpoint. Religious clerics can be seduced by an autocrat and political stability is at stake. The autocrat's decisions consist of two measures susceptible of antagonising religious clerics: adopting secular reforms and unduly appropriating part of national wealth, which generally are complement. Compared to centralized religions, decentralized religions, such as Islam, tend to discourage secular reforms and corruption but those effects are not guaranteed if the autocrat accepts political instability. The main hypotheses and the central results of the theory are illustrated with regime case studies that refer to contemporary times
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