Vorgehensmodelle bei der Entwicklung von CAL-Software

<br

Erwartungen der Praxis an CAL:Ergebnisse einer Expertenbefragung

<br

Editorial: E-Learning-Strategien für die Hochschullehre

27.04.2015 | Sabine Seufert (St. Gallen), Martin Ebner, Michael Kopp (Graz) & Bettina Schlass (Amsterdam

Die NetAcademy als Medium für die Learning Community eines Masterprogramms an der Universität St. Gallen

Aus der Einleitung: 'Seit einiger Zeit erfährt der Begriff „Community“ wieder eine starke Verbreitung, nicht zuletzt aufgrund der explosionsartigen Verbreitung des Internets und dessen Akzeptanz. Auch im Bereich Aus- und Weiterbildung tragen neue Informations- und Kommunikationstechnologien zu Veränderungen bei. Wissen kann schneller, effizienter und in einer global zugänglichen Form gesammelt, generiert, geteilt sowie verteilt werden. Neue Formen des Lernens und des Lehrens etablieren sich. Das Konzept der „Learning Communities“, die basierend auf einer Internet-Plattform auch eine „Virtuelle Gemeinschaft“ charakterisieren können, stellt dabei ein neuer Ansatz dar

Urban agriculture: a global analysis of the space constraint to meet urban vegetable demand

Urban agriculture (UA) has been drawing a lot of attention recently for several reasons: the majority of the world population has shifted from living in rural to urban areas; the environmental impact of agriculture is a matter of rising concern; and food insecurity, especially the accessibility of food, remains a major challenge. UA has often been proposed as a solution to some of these issues, for example by producing food in places where population density is highest, reducing transportation costs, connecting people directly to food systems and using urban areas efficiently. However, to date no study has examined how much food could actually be produced in urban areas at the global scale. Here we use a simple approach, based on different global-scale datasets, to assess to what extent UA is constrained by the existing amount of urban space. Our results suggest that UA would require roughly one third of the total global urban area to meet the global vegetable consumption of urban dwellers. This estimate does not consider how much urban area may actually be suitable and available for UA, which likely varies substantially around the world and according to the type of UA performed. Further, this global average value masks variations of more than two orders of magnitude among individual countries. The variations in the space required across countries derive mostly from variations in urban population density, and much less from variations in yields or per capita consumption. Overall, the space required is regrettably the highest where UA is most needed, i.e., in more food insecure countries. We also show that smaller urban clusters (i.e., <100 km2 each) together represent about two thirds of the global urban extent; thus UA discourse and policies should not focus on large cities exclusively, but should also target smaller urban areas that offer the greatest potential in terms of physical space

Emergence of communities on a coevolutive model of wealth interchange

We present a model in which we investigate the structure and evolution of a random network that connects agents capable of exchanging wealth. Economic interactions between neighbors can occur only if the difference between their wealth is less than a threshold value that defines the width of the economic classes. If the interchange of wealth cannot be done, agents are reconnected with another randomly selected agent, allowing the network to evolve in time. On each interaction there is a probability of favoring the poorer agent, simulating the action of the government. We measure the Gini index, having real world values attached to reality. Besides the network structure showed a very close connection with the economic dynamic of the system.Comment: 5 pages, 7 figure

Picosecond Nonlinear Relaxation of Photoinjected Carriers in a Single GaAs/AlGaAs Quantum Dot

Photoemission from a single self-organized GaAs/AlGaAs quantum dot (QD) is temporally resolved with picosecond time resolution. The emission spectra consisting of the multiexciton structures are observed to depend on the delay time and the excitation intensity. Quantitative agreement is found between the experimental data and the calculation based on a model which characterizes the successive relaxation of multiexcitons. Through the analysis we can determine the carrier relaxation time as a function of population of photoinjected carriers. Enhancement of the intra-dot carrier relaxation is demonstrated to be due to the carrier-carrier scattering inside a single QD.Comment: 4 pages, 4 figures, to be published in Phys. Rev. B, Rapid