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101.
The ecological paradigm has become a powerful framework for understanding how teachers and students negotiate the learning environment. This article articulates the ecological paradigm into a more cohesive framework and expands it using influential work from the sociology of physical education. First, we explain several core concepts of ecological theory and explain how they fit together. Next, we overview past ecological work in each of the three main task systems, while integrating literature from outside traditional ecological theory to show how it better enhances the paradigm's usefulness. We show how culturally relevant content, student ownership/control, and cooperation/competition provide richness in further explaining the instructional task system. Similarly, we broaden the student social system into a social task system with three dimensions: relationships between teachers and students, relationships among students, and the social climate of the school. 相似文献
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Phonological skills and comprehension failure: A test of the phonological processing deficit hypothesis 总被引:2,自引:1,他引:1
Shankweiler and colleagues argue that text comprehensionproblems in young children arise from phonological processingdifficulties. Their work has focused on children with poor wordreading ability. We investigated this hypothesis for children whoexperience comprehension difficulties in the presence of age-appropriate word reading skills. We found that good and poorcomprehenders performed comparably on various measures ofphonological processing and differed on a task that made greaterdemands on working memory, Bradley and Bryant's odd-word-outtask. In a final study, hierarchical regression analyses supportedthis distinction: the odd-word-out task was a strong predictor ofreading comprehension performance even after IQ, vocabulary and single word reading had been controlled for, but a lessmemory-dependent phonological task was not. These studiessupport previous work which indicates that poor comprehenders'problems arise from higher-level processing difficulties. 相似文献
104.
Investigating the causes of reading comprehension failure: The comprehension-age match design 总被引:1,自引:0,他引:1
The reading-level (or reading-age) match design has become a widely-used tool for investigating the possible direction of the relation between particular skills and word reading ability: Cause or consequence. This paper outlines an analogous method for identifying candidate causes of reading comprehension failure, the `comprehension-age match design' and discusses the strengths and limitations of this design. 相似文献
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Discoloured 18-carat gold decorations from Sweden have been analysed by scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray electron spectroscopy (XPS)/electron spectroscopy for chemical analysis (electron spectroscopy).The original gold composition was close to 75% gold, 13% silver, and 12% copper. After manufacture, many details were boiled in sulphuric acid. As a consequence of this, the surfaces are irregular and porous with a gold concentration around 90% and with less than 1% copper. With XPS the outermost 10–20 atomic layers could be examined. No copper was present here, and the silver concentration was significantly higher. Also carbon, sulphur, oxygen, and (in one case) chlorine were present. The valence numbers indicated that gold only occurred in its metallic state, while silver (as Ag+) was preferably associated with sulphur to form black silver sulphide (Ag2S). The grey discolorations are basically due to silver sulphide and organic dirt. Sometimes green, violet, and ‘copper-shining’ colours occur, presumably as a result of light refraction phenomena. 相似文献
109.
ABSTRACTHampton Court Palace’s Great Hall located in Surrey, UK, is a magnificent late medieval hall. Its large hammer-beam roof is sumptuously decorated while its walls for the past century have been rehung with Henry VIII’s five-hundred-year-old tapestries illustrating The Story of Abraham, and one of the most internationally significant sets of sixteenth-century tapestries, commissioned for the same hall. This paper presents research which began in 2007, exploring conservation solutions based on evidence-based decision-making, through to successful implementation of measures that conserve these invaluable tapestries without damaging the aesthetic or physical integrity of the Great Hall. The impacts of environmental exposure conditions mapped in detail were assessed to evaluate risk for each tapestry. Next, feasibility studies identified the effectiveness of a range of potential mitigating options to address each local risk, now being incrementally implemented over many years. The research has enabled us to develop, test and deliver permanent interventions that have – when considered together as a holistic management regime – allowed the tapestries to remain in situ. These interventions will continue to be monitored and evaluated for at least a further year to confirm their effectiveness. 相似文献
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Microfibril angle (MFA) – the orientation of cellulose fibres in the S2 layer of the secondary cell wall – is a key determinant of the stiffness and strength of timber. The microfibril angle depends on the way in which the timber was grown and its position within the tree. Microfibril angle can be measured by X-ray diffraction and other methods, but the methods in current use are slow or require advanced instrumentation. The aim of this study was to explore the use of polarised Fourier transform infrared (FTIR) microscopy as a relatively fast and inexpensive method for measuring MFA in historic Scots pine (Pinus sylvestris L.). The FTIR measurements were calibrated against X-ray measurements of MFA in modern Scots pine. We observed a wide range in MFA values and a radial pattern of MFA similar to modern Scots pine in undecayed Scots pine heartwood from sixteenth and seventeenth century beams in Scottish secular buildings. The density of the heartwood was also similar to modern plantation-grown Scots pine despite the much slower growth rate recorded in the ring widths of the historic timber. The sapwood, which had been attacked by both insect pests and fungi, showed an erratic reduction in density and a large increase in MFA compared to the modern material. The increased sapwood MFA was attributed to selective destruction of the S2 layer of the wood cell walls by fungal decay. Using MFA measurements in conjunction with density offers the possibility to estimate the mechanical properties of sound historic pine timber, to detect fungal decay more sensitively than by density alone, and to distinguish between pest and fungal attack in a way that relates directly to the remaining mechanical performance of the timber. 相似文献