Semihydroponic and ebb-and-flow systems for calla lily cultivation

Micropropagation of calla lily (Zantedeschia rehmannii)

The aim of this study was to develop methods for the in vitro propagation of Zantedeschia rehmannii. Zantedeschia rehmannii tuber fragments (1 cm2) containing eyes were soaked for 30 s in a solution containing 100 mg dm-3 L-ascorbic acid (AA) before transfer to culture vessels containing an MS medium supplemented with BAP (0 to 3 mg dm-3). Cultures were maintained in darkness. Soaking explants ...

The ebb and flow of online learning

Past research has suggested that Csikszentmihalyi’s flow theory describes a state that should be supportive of a student’s learning. This article reports on research that uses the constructs of flow to explore learning in an online environment. An experiment was carried out in which students worked through a learning sequence in the physics domain that had varying degrees of interactivity. Thei...

EBB and Flow in Social Psychiatry **

I would like to begin by expressing my sense of the honor done me by the invitation to deliver this Lecture, instituted in memory of a brilliant investigator of social psychiatry. Wherever psychiatrists meet to discuss the social aspects of their subject, the outstanding contributions of this school are certain to be quoted. Need I say that these contributions are embodied to a large extent in ...

The ebb and flow of asthma.

The Ebb and Flow of Controversial Debates on Social Media

We explore how the polarization around controversial topics evolves on Twitter – over a long period of time (2011 to 2016), and also as a response to major external events that lead to increased related activity. We find that increased activity is typically associated with increased polarization; however, we find no consistent long-term trend in polarization over time among the topics we study.