An argument for vindicating a Marxist ontology in environmental education research

Abstract

In this paper, we analyse the status and significance of adopting a Marxist ontological perspective in the field of Brazilian environmental education. We draw on the concept of labour developed by Marx, where labour is used as a category to articulate the relationships humans establish with nature and which, historically, have an impact on their living conditions. Given the ongoing process of destroying the material basis of life under a Capitalist means of production, we argue that environmental educators and researchers require refinements to the theoretical and methodological frameworks they use to understand contradictions between development and sustainability in Brazil. This includes meeting their responsibilities to help others and themselves overcome the current capitalist model governing the social and material production of life.     

Evaluating the Effectiveness of Integrating Food Science Lessons in High School Biology Curriculum in Comparison to High School Chemistry Curriculum

Historically, high school chemistry has been the predominate venue for the introduction of food science curriculum to students. With the current decline in chemistry as a required course for graduation, the possibility of exposure to food science in high school could equally decline. The purpose of this research was to determine if high school students in a biology class without a chemistry background could comprehend eight basic food science principles equally as well as students in a chemistry class that were taught the same principles. This study assessed baseline knowledge of high school students, determined the effect of food science‐based lessons on baseline knowledge and level of understanding, and determined the effect of food science‐based lessons on students’ awareness of and interest in food science. Baseline knowledge and awareness of food science was low. Food science‐based instruction resulted in higher posttest scores. Results indicated no differences in students’ knowledge base and level of understanding between biology and chemistry classes and supported the idea of further incorporating a food science curriculum into high school biology.     

偏光显微镜在壁画颜料分析中的应用

近年来偏光显微镜在文物保护上的应用越来越广泛 ,尤其是在壁画地仗、颜料成分及病害分析等方面 ,本文列举了偏光显微镜在颜料分析中多方面的应用。     

Youth leaders' perceptions of commitment to a responsibility-based physical activity program

This study extended Schilling's (2001) study by investigating program commitment among a larger (N = 12), older (M = 16.7 years), and more experienced (M = 5.96 years) sample of participants in the Project Effort Youth Leader Corps. Individual interviews elicited a greater number and specificity of themes. Program-related barriers included logistics, structure, and relationships, and personal-related barriers included perceived alternatives, personal characteristics, and "real-life" responsibilities. Similar to Schilling's (2001) earlier study, antecedents grouped under program environment, program structure, relationships, and personal characteristics. Participants also described outcomes in terms of behavior and emotional involvement but reported more themes related to leadership. Results are discussed in terms of consistencies and changes over time and implications for program development, expansion, and evaluation.     

The influence of deformation on barbell mechanics during the clean pull

For simplicity of biomechanical analyses, the weightlifting barbell is typically modelled as a rigid, non-deformable object. Most coaches and weightlifters, however, are aware of the elastic nature of the barbell, and its influence on the successful completion of lifting attempts. Variables such as velocity, work performed, and power output are indicators of the quality of performance during the snatch, clean, and related weightlifting pulling movements. The aim of this study was to establish whether differences exist in determining these biomechanical parameters when the centre of the barbell is analysed compared with each end of the barbell. Nine men performed three maximal-effort repetitions in the clean pull exercise at 85% of their self-reported single repetition maximum (1-RM) clean (90–155 kg) using a barbell instrumented for mechanical analysis. Results indicated that peak barbell speed was 5–30% (P < 0.05) lower for the centre of the barbell than the ends. Although differences (P < 0.05) in kinetic and potential energy were found between the centre and ends of the bar, differences between total work performed were small ( < 6%; P < 0.05) and no differences were observed for average power (P > 0.05). Although approximately the same work and power occur for the centre and ends of the barbell, they manifest as different kinematics as a result of the elastic nature of the equipment. The elastic characteristics should be considered when selecting instrumentation and variables for research involving barbells. Coaches should be aware of the elasticity of barbells, including selecting appropriate viewing angles as well as understanding how deformation may affect the ends of the barbell relative to the centre.     

Joint stiffness and running economy during imposed forefoot strike before and after a long run in rearfoot strike runners

Research has focused on the effects of acute strike pattern modifications on lower extremity joint stiffness and running economy (RE). Strike pattern modifications on running biomechanics have mostly been studied while runners complete short running bouts. This study examined the effects of an imposed forefoot strike (FFS) on RE and ankle and knee joint stiffness before and after a long run in habitual rearfoot strike (RFS) runners. Joint kinetics and RE were collected before and after a long run. Sagittal joint kinetics were computed from kinematic and ground reaction force data that were collected during over-ground running trials in 13 male runners. RE was measured during treadmill running. Knee flexion range of motion, knee extensor moment and ankle joint stiffness were lower while plantarflexor moment and knee joint stiffness were greater during imposed FFS compared with RFS. The long run did not influence the difference in ankle and knee joint stiffness between strike patterns. Runners were more economical during RFS than imposed FFS and RE was not influenced by the long run. These findings suggest that using a FFS pattern towards the end of a long run may not be mechanically or metabolically beneficial for well-trained male RFS runners.     

The influence of deformation on barbell mechanics during the clean pull

For simplicity of biomechanical analyses, the weightlifting barbell is typically modelled as a rigid, nondeformable object. Most coaches and weightlifters, however, are aware of the elastic nature of the barbell, and its influence on the successful completion of lifting attempts. Variables such as velocity, work performed, and power output are indicators of the quality of performance during the snatch, clean, and related weightlifting pulling movements. The aim of this study was to establish whether differences exist in determining these biomechanical parameters when the centre of the barbell is analysed compared with each end of the barbell. Nine men performed three maximal-effort repetitions in the clean pull exercise at 85% of their self-reported single repetition maximum (1-RM) clean (90-155 kg) using a barbell instrumented for mechanical analysis. Results indicated that peak barbell speed was 5-30% (P < 0.05) lower for the centre of the barbell than the ends. Although differences (P < 0.05) in kinetic and potential energy were found between the centre and ends of the bar, differences between total work performed were small (< 6%; P < 0.05) and no differences were observed for average power (P > 0.05). Although approximately the same work and power occur for the centre and ends of the barbell, they manifest as different kinematics as a result of the elastic nature of the equipment. The elastic characteristics should be considered when selecting instrumentation and variables for research involving barbells. Coaches should be aware of the elasticity of barbells, including selecting appropriate viewing angles as well as understanding how deformation may affect the ends of the barbell relative to the centre.