La géométrie projective à l'école

Sans résuméTravail effectué dans le cadre du groupe de recherche en didactique de la mathématique du Conseil National des Recherches.     

体力活动与癌症生存研究的10大问题

摘要：今天的美国有1 400万的癌症存活者,其中的很多存活者中都接受了多种治疗,包括手术、放疗、化疗、靶向治疗等。这些治疗能够延长生存时间,但同时也会带来很多急慢性的副作用,危害健康,影响生活质量。体力活动（PA）与癌症生存这一领域发展迅速,主要研究PA对癌症患者的影响。基于该领域的研究进展,提出了以下10大研究问题：1）PA能够降低癌症复发风险、和/或提高存活吗？2）PA能够影响癌症治疗决策、完成率、和/或患者对治疗的反应吗？3）癌症存活者的最佳运动处方是什么？4）静坐少动行为对癌症存活者有何影响？5）癌症存活者最有效的体力活动干预方案是什么？6）哪些癌症会影响病人对PA的反应？7）癌症存活者进行体力活动时需要注意的安全问题有哪些？8）哪些具体的癌症症状可以由PA解决？9）对于癌症晚期患者,体力活动还有何作用？10）如何将体力活动研究结果转化到临床和社区肿瘤实践中来？上述问题的回答至关重要,这不仅关系到体力活动和癌症存活这一研究领域的发展,更重要的是,能够为每年数百万新诊断为癌症的病人、正在接受癌症治疗的病人、治疗结束处于恢复中的病人或是那些正在与晚期癌症抗争的病人带来福音。     

Improving children's working memory and classroom performance

Previous research has demonstrated close relationships between working memory and children's scholastic attainment. The aim of the present study was to explore a method of improving working memory, using memory strategy training. Two hundred and fifty‐four children aged five to eight years were tested on measures of the phonological loop, visuo‐spatial sketchpad and central executive components of the multiple component model of working memory. Subgroups of children also completed tasks of following instructions and mental arithmetic in the classroom, and standardised tests of reading, arithmetic and mathematics. Half of the children then used Memory Booster, a computer game that teaches memory strategies, over a period of six to eight weeks. All the children were then retested on the memory and ability measures. The standardised tests were also administered five months later. The results revealed that working memory strategy training resulted in significant improvements in tasks assessing the phonological loop and central executive components of working memory, and tasks assessing following instructions and mental arithmetic in the classroom. However, no improvements were observed on standardised tests of reading, arithmetic or mathematics, either immediately following training or five months later. The results are discussed in terms of implications for educational practice.     

A single session of treadmill running has no effect on plasma total ghrelin concentrations

Abstract

Ghrelin is a hormone that stimulates hunger. Intense exercise has been shown to temporarily suppress hunger after exercise. In the present study, we investigated whether post-exercise hunger suppression is mediated by reduced plasma total ghrelin concentrations. Nine men and nine women participated in the study. Their mean physical characteristics were as follows: age 24.8 (s _x  = 0.9) years, body mass index 22.9 (s _x  = 0.6) kg · m^?2, maximal oxygen uptake ([Vdot]O_2max) 57.7 (s _x  = 2.2) ml · kg^?1 · min^?1. The participants completed two 3-h trials (exercise and control) on separate days in a randomized balanced design after overnight fasts. The exercise trial involved a 1-h treadmill run at 73.5% of [Vdot]O_2max followed by 2 h of rest. The control trial consisted of 3 h of rest. Blood samples were collected at 0, 0.5, 1, 1.5, 2, and 3 h. Total ghrelin concentrations were determined from plasma. Hunger was assessed following blood sampling using a 15-point scale. The data were analysed using repeated-measures analysis of variance. Hunger scores were lower in the exercise trial than in the control trial (trial, P = 0.009; time, P < 0.001; trial × time, P < 0.001). Plasma total ghrelin concentrations did not differ between trials. These findings indicate that treadmill running suppresses hunger but this effect is not mediated by changes in plasma total ghrelin concentration.     

Educational placements and National Curriculum Key Stage 2 test outcomes of children with a history of specific language impairment

As part of their longitudinal investigations of a large cohort with a history of specific language impairment (SLI), Professor Gina Conti-Ramsden and her research team based at the School of Education, University of Manchester, Dr Emma Knox, Dr Nicola Botting and Dr Zoë Simkin report on the changing educational placements and National Curriculum assessment outcomes of 200 children at 11 years. Teacher questionnaires reporting on the Year 6 primary education placements of the sample reveal details about the long-term educational needs of children with SLI.
Furthermore, in exploring the experiences of the sample in the National Curriculum Key Stage 2 tests the present study found that children with SLI perform poorly relative to national expectations of levels of achievement across all tests. At present there are no guidelines for supporting children with SLI in relation to National Curriculum tests and the present data suggests there is an obvious need for these to be developed.     

在雨中飞奔

~~在雨中飞奔@小Q     

Compressive Strength of Hydrostatic-Stress-Sensitive Materials at High Strain-Rates

Many engineering materials demonstrate dynamic enhancement of their compressive strength with the increase of strain-rate, which have been included in material models to improve the reliability of numerical simulations of the material and structural responses under impact and blast loads. The strain-rate effects on the dynamic compressive strength of a range of engineering materials which behave in hydrostatic-stress-sensitive manner were investigated. It is concluded that the dynamic enhancement of the compressive strength of a hydrostatic-stress-sensitive material may include inertia-induced lateral confinement effects, which, as a non-strain-rate factor, may greatly enhance the compressive strength of these materials. Some empirical formulae based on the dynamic stress-strain measurements over-predict the strain-rate effects on the compressive strength of these hydrostatic-stress-sensitive materials, and thus may over-estimate the structural resistance to impact and blast loads, leading to non-conservative design of protective structures.     

Using communities of practice to enhance interdisciplinary teaching: lessons from four Australian institutions

We report on the establishment of communities of practice at four Australian institutions and evaluate their effectiveness and durability as a means of building staff and institutional capacity for interdisciplinary teaching. A community of practice approach is a potentially valuable methodology for overcoming dynamics of fragmentation, isolation and competition within universities. The communities we established were anchored by a shared focus on the topic of climate change and they worked collaboratively to build relationships of trust and reciprocity between teachers in a wide range of disciplines. The aim of each community was to improve the teaching of climate change through enabling members to integrate diverse disciplinary perspectives, to teach collaboratively, to promote innovation through exchange and to demonstrate leadership within their institutions. The key factors that made our communities effective and durable are: (1) designation of two leadership roles, activator and facilitator, (2) provision for institutional autonomy in domesticating the model to fit local circumstances and (3) a pragmatic emphasis on opportunities for teaching innovation and leadership within existing administrative structures, teaching programs and workloads. We conclude that suitably designed and resourced communities of practice are a viable means of improving interdisciplinary teaching of complex problems by facilitating both staff development and institutional learning.