CHANGES IN PARTICIPATION AND THE DEVEOLOPMENT OF A LEARNING COMMUNITY FOR ENGLISH TEACHERS IN A VIDEO CLUB IN ALBANIA

This study investigated a group of English teachers’ interactions watching video of their classrooms, in what is called a video club, for the purpose of professional development. Changes in both what and how teachers discussed, along with how the club developed as a learning community were investigated using recordings of their conversations in two early and two late video club meetings. The focus of what teachers discussed changed from the early to the late meetings and a pattern of discussion emerged in the later meetings. Significant changes in the number of ideas teachers put forth for discussion and the number of clarifying comments teachers provided were noted. The video club developed some aspects of a learning community, particularly in participants’ ability to focus their discussion on the specific issues of teaching and learning in the video, but either failed to develop or showed cyclical development in other ways

What is the role of the kink instability in solar coronal eruptions

ABSTRACT We report the results of two simple studies which seek observational evidence that solar coronal loops are unstable to the MHD kink instability above a certain critical value of the total twist. First, we have used Yohkoh SXT image sequences to measure the shapes of 191 X-ray sigmoids and to determine the histories of eruption (evidenced by cusp and arcade signatures) of their associated active regions. We find that the distribution of sigmoid shapes is quite narrow and the frequency of eruption does not depend significantly on shape. Second, we have used Mees Solar Observatory vector magnetograms to estimate the largescale total twist of active regions in which flare-related signatures of eruption are observed. We find no evidence of eruption for values of large-scale total twist remotely approaching the threshold for the kink instability