Johannes Emden

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Virtpresenter is a system for recording lectures and for re-using recorded contents in other didactic scenarios. Here we demonstrate how the interaction of earlier visitors in form of footprints can be used for extracting relevant passages in time based media. We illustrate how to extract online web lecture snippets for enriching static contents of a course(More)
1. Numerous compounds and changes in physical state functions shift the membrane potential of vascular smooth muscle to more negative values. The consequence is a vasodilatation because Ca2+ channels are closed. K+ channel opening frequently causes the hyperpolarization. 2. Acidification of the blood substitute solution and a fall in O2 partial pressure(More)
This paper describes an approach to integrate lecture recordings, based on the virtPresenter framework, within social networks. A lot of social networks have recently begun to provide application programming interfaces (APIs) for external applications, allowing access to users' profile information and their friendship relations. The project " social(More)
For a study of the colonisation of the IJsselmeerpolders by fungi, attention was fixed on the cellulose-decomposing fungi, since these are considered to represent the more stable part of the mycoflora of soils. If one assumes that in the North East Polder, cultivated for approximately 25 years, the fungal population is approaching stability, the progress of(More)
1 Disinfection of seed tubers with proprietary organo-mercury compounds effectively controlsRhizoctonia solani in the seed potato growing area of Noord-Holland. 2 The beneficial effect of disinfection is also produced if the seedtubers do not bear sclerotia, because the fungus inoculum may be present as mycelial threads in the cavities around the eyes. 3(More)
User awareness has become a popular feature in many social web applications. In classic text-based web-systems, user awareness features show how many users are online in a web application or how many users are accessing the same web page. When time based media like web lectures are concerned this approach comes to its limits since time-based media are(More)
(1). PCNB was found to lower the incidence of common scab if applied shortly before planting and earthing up, after preparing the seed-bed. Under conditions prevailing in the Netherlands and when using susceptible varieties the optimal rate of application may range between 60 and 100 kg of active substance per ha. A residual effect was found to last into(More)