The role of wood in meeting current and future global energy needs

Recent surveys by the FAO and other organisations have shown that worldwide the amount of wood used as fuel is far greater than had been supposed. It probably exceeds one billion tonnes annually, comparable with the quantity used for all other purposes combined. This has stimulated interest in the economic viability of growing wood as a fuel crop, particularly by coppicing.     

The effect of bilateral asymmetry of muscle strength on the height of a squat jump: a computer simulation study

The aim of this study was to examine the effect of bilateral asymmetry of muscle strength on maximal height of the squat jump. A computer simulation technique was used to develop two kinds of 3D human lower limb musculoskeletal model (model-symmetry and model-asymmetry). The total muscle strength of the two models was set to be identical. Bilateral muscle strength was equal in the model-symmetry simulation, while the model-asymmetry simulation was performed with a 10% bilateral strength asymmetry. A forward dynamics approach was used to simulate squat jumps. The squat jumps were successfully generated, producing jump heights of 0.389 m for model-symmetry and 0.387 m for model-asymmetry. The small difference in height (0.5%) indicated that the effect of the 10% bilateral asymmetry of muscle strength on jump height is negligible. With model-asymmetry, the strong leg compensated for the muscle strength deficit of the weak leg. Importantly, the mono-articular and large extensor muscles of the hip and knee joint of the strong leg, including the gluteus maximus, adductor magnus, and vasti, compensated for the muscle strength deficit of the weak leg.     

The Recruitment of New Teachers from Minority Ethnic Groups

This article reports on part of a larger, ongoing two-year investigation supported by the Teacher Training Agency into the recruitment of new teachers from minority ethnic backgrounds via Postgraduate Certificate in Education (PGCE) courses in England. The authors focus here on interviews with admissions tutors, course directors and other senior staff at teacher training institutions. The interviews revealed differences between institutions in the measures taken to attract minority ethnic students. The research indicates a need for much clearer guidelines for admissions tutors on the issues surrounding the question of 'positive action' on the recruitment of new teachers from minority ethnic groups.     

The La Trobe Twin Study: a genetic approach to the structure and development of cognition in twin children

Twins are particularly useful for developmental behavior genetics, if adequate consideration is given to the possibilities of twin-singleton differences and of data from twins being unrepresentative of the entire population. As an alternative to existing analyses in the developmental behavior genetics of cognition, the covariance structure analysis method in biometrical genetics involving twins and other relatives has the potential for dissecting the determinants of the structure of cognitive abilities and how these change during childhood, as well as checking on the adequacy of twin data. Designed with these aims in mind, the La Trobe Twin Study is a mixed longitudinal analysis of 1,356 twins, their siblings, and cousins, who are followed between the ages of 3 and 15 years on a battery of physical and behavioral tests. The criteria for choosing behavioral tests in such a project are discussed, along with the comprehensive series of questionnaires necessary to examine the children's development in the context of the stresses a multiple birth may impose on a family. In discussion of methods of analysis, 2 points are emphasized: (1) Twin-singleton differences are specific to particular abilities rather than being general, and (2) the incidence of family changes and stresses in such that these should be considered among the environmental effects on development along with the more usual indices of family environment.     

Use of concept mapping to integrate the different perspectives of designers and other stakeholders in the development of e-learning materials

Multi-disciplinary teams and stakeholders are involved in the production of e-learning materials and all have differing and valuable perspectives. A range of factors such as availability of new learning technologies, pedagogy or the learning market, may direct the design process. This article argues that a constructivist methodology for course design enables a project manager to build on all contributors' perspectives in a "bottom up" rather than a "top down" approach and be aware of any weaknesses and undesirable dominating influences. Concept mapping provided the basis for an e-learning development project at the University of Surrey to develop such a constructivist methodology. The design team and wider stakeholders each produced individual concept maps and were analysed to identify both commonalties and unique contributions that might influence design. The project manager then integrated the individual maps to produce an overall map of the project and found the process valuable for a more critical and holistic approach to directing the project.     

Changes in muscle-tendon length during the take-off of a running long jump

The aims of this study were to determine: (1) the modes of action of selected muscles of the supporting leg during the take-off of a running long jump; (2) whether the instant at which maximum knee flexion is recorded is a valid indicator of the instant these muscles change their modes of action; and (3) the relationships between the actions of these muscles and the change in the vertical velocity of the centre of mass during the take-off. Eleven elite, female long jumpers performed six jumps from a full-length approach. A model of selected muscles of the jumping leg was developed to estimate muscle-tendon lengths from segment positions obtained using cinematography. Only half of the muscles exhibited a lengthening-shortening sequence of activity. The instant at which maximum knee flexion was recorded was a poor indicator of when the muscles changed from eccentric to concentric activity. The more the vasti muscles were stretched, the larger the gain in vertical velocity; the longer the triceps surae muscles at touchdown, the more they were stretched, and the faster they were stretched, the larger the gain in vertical velocity. Enhancement through use of the stretch-shortening cycle did not make a significant contribution to vertical velocity via the actions of the vasti and triceps surae muscles.     

KEY INFORMANTS' PERSPECTIVES ON TEACHER LEARNING IN SCOTLAND

ABSTRACT:   This article outlines the policy context for teachers' learning and continuing professional development in Scotland and considers this in relation to the perspectives of key informants gained through interview. The analysis draws on a triple-lens conceptual framework and points to some interesting contradictions between the policy text and the expressed aspirations of the interviewees. Current policy and the associated structural arrangements are viewed as broadly positive, but interviewees express concerns that an unintended emphasis on contractual arrangements might inhibit the more transformative elements of professional learning.