In order to support professional development of their teachers 14 Dutch secondary schools developed and implemented a series of interventions. The concept of School as Professional Learning Community was used to frame these school interventions. Data were collected through project documents, interviews with school principals and project leaders, group interviews with teachers and focus groups with project leaders. Interventions can be grouped into five clusters: 1) Shared school vision on learning; 2) Professional learning opportunities for all staff; 3) Collaborative work and learning; 4) Change of school organisation, and 5) Learning leadership. Interventions aimed at teacher-leaders, team leaders and school principals were relatively rare. Interventions belonging to the clusters Professional learning opportunities and Collaborative work and learning were the ones most frequently mentioned including formal and informal teacher groups working and learning together. In general, we conclude that the more embedded an intervention was in the organisation and culture of a school, the more sustainable it appeared to be.

No abstract

Three species of intertidal diatoms were kept in unialgal and mixed cultures forming mats on the surface of clean sand. Interaction between the species was studied by 25 d incubation in serially diluted cultures, allowing natural population densities to be maintained. Abundance of species in mixed cultures was primarily determined by their capacities to thrive under inorganic carbon limitation (and associated conditions) and by their capacity to produce inhibitory substances. The range of physico-chemical conditions exploited by the test species narrowed considerably during interaction with a competitor. The relevance of the experiments for the interpretation of distribution patterns of estuarine diatom species is discussed as is the limited information available on mechanisms for carbonfixation in these organisms.

No abstract

A multiple case study has been carried out of four teacher groups who engaged in collective lesson design, observation, and reflection to support their professional learning. The teacher groups were examined on what and how they learned from their collaboration over time. For each meeting, teachers' learning logs and transcripts were analysed. The results show that the groups differed in the amount, consistency, and stability of self-reported learning outcomes throughout the meetings. Differences between groups also relate to the number and type of dialogic moves between the teachers within each group. A main conclusion includes that challenging each other in their dialogues supported teachers' learning. Additional explanations of learning outcomes relate to teachers' collective participation and facilitation in the group.