Intuitive ideas and scientific explanations as parts of students' developing understanding of biology: The case of evolution

Questions concerning 13–16 year old students' developing understanding of different biological concepts related to the theory of evolution of species are focused. The aim is to get more detailed examples of the ways in which students understand complex biological concepts and the development of these concepts. Data were collected from two different periods: at the beginning of the seventh and at the end of the ninth grade of the Swedish compulsory school. The examples given show how students, in various ways, construct and develop their understanding of animal and plant adaptation to nature, with the help of their biological knowledge as well as by alternative and more intuitive ideas about the function of nature. The varying abilities of students to express their ideas are discussed as well as different arguments concerning the student's difficulties in adapting to scientific ideas from more intuitive ideas.     

Conflict and Its Resolution in Small Groups of One- and Two-Year-Olds

48 1- and 48 2-year-olds were observed in groups of 3 for 25 min on 2 consecutive days, once with ample resources and once with scarce resources. The triads were composed of either 2 girls and a boy or 2 boys and a girl, and duplicate copies of toys were available for half the groups. Their conflicts contained interpersonal features and were more affected by social influences than by the availability of resources. Contrary to expectations, scarcity of resources did not result in increased conflict. In fact, 2-year-olds were more likely to resolve conflict by sharing when toys were scarce. The provision of duplicates decreased the probability of conflict, but many conflicts occurred even when a duplicate was easily accessible. The form of conflict depended on the children's age and the gender composition of the group. Older children and groups dominated by boys, relative to younger children and groups dominated by girls, were less likely to use force and more likely to resolve disputes in prosocial ways. Taken together, these findings provide further evidence for the social nature of conflict in the first few years of life.     

Teachers’ beliefs about issues in the implementation of a student-centered learning environment

Teachers’ implementation of technology-enhanced student-centered learning environments (SCLEs) will be affected by their beliefs about effective practices. In order for student-centered programs to be used as intended, designers must be aware of the key issues that will shape their implementation and the beliefs teachers hold about these issues. This case study examined 15 teachers’ beliefs about student-centered learning as they implemented Alien Rescue, a computer-based program for middle school science that was designed to create a SCLE in the classroom. Considerations for the design of similar programs are offered.     

Two conceptions of fraction equivalence

Educational Studies in Mathematics - In this study, we present a mathematical analysis distinguishing two conceptions of equivalence: proportional equivalence and unit equivalence. These two...     

吊索训练对高水平足球运动员平衡能力、踢球速度和躯干(肌肉力量)稳定性的改善

研究目的:通过量化的数据,确定以稳定性为核心的吊索训练计划(SET)对高水平足球运动员身体位置平衡能力、踢球速度和力量的作用.     

Measuring Sojourner Adjustment among American students studying abroad

The literature on "Sojourner Adjustment," a term expanding on the acculturation concept to apply to groups residing temporarily in foreign environments, suggests that engagement, participation, and temporary integration into the host culture may contribute to less psychological and sociocultural difficulty while abroad. The present study was designed to establish a brief multi-component measure of Sojourner Adjustment (the Sojourner Adjustment Measure; SAM) to be used in work with populations residing temporarily in foreign environments (e.g., international students, foreign aid workers). Using exploratory and confirmatory factor analyses on a sample of 248 American study abroad college students, we established a 24-item measure of Sojourner Adjustment composed of four positive factors (social interaction with host nationals, cultural understanding and participation, language development and use, host culture identification) and two negative factors (social interaction with co-nationals, homesickness/feeling out of place). Preliminary convergent validity was examined through correlations with established measures of acculturation. Further research with the SAM is encouraged to explore the relevance of this measure with other groups of sojourners (e.g., foreign aid workers, international businessmen, military personnel) and to determine how SAM factors relate to psychological well-being, health behaviors, and risk behaviors abroad among these diverse groups.     

Exercise, nutrition and immune function

Strenuous bouts of prolonged exercise and heavy training are associated with depressed immune cell function. Furthermore, inadequate or inappropriate nutrition can compound the negative influence of heavy exertion on immunocompetence. Dietary deficiencies of protein and specific micronutrients have long been associated with immune dysfunction. An adequate intake of iron, zinc and vitamins A, E, B6 and B12 is particularly important for the maintenance of immune function, but excess intakes of some micronutrients can also impair immune function and have other adverse effects on health. Immune system depression has also been associated with an excess intake of fat. To maintain immune function, athletes should eat a well-balanced diet sufficient to meet their energy requirements. An athlete exercising in a carbohydrate-depleted state experiences larger increases in circulating stress hormones and a greater perturbation of several immune function indices. Conversely, consuming 30-60 g carbohydrate x h(-1) during sustained intensive exercise attenuates rises in stress hormones such as cortisol and appears to limit the degree of exercise-induced immune depression. Convincing evidence that so-called 'immune-boosting' supplements, including high doses of antioxidant vitamins, glutamine, zinc, probiotics and Echinacea, prevent exercise-induced immune impairment is currently lacking.