"Wenn Ihnen das Leben eine Zitrone gibt, machen Sie Limonade daraus"

Sehr lösungs- und praxisorientiert widmet sich Eva-Maria Schumacher in ihrem Beitrag dem Umgang mit Lehrsituationen, die oft als schwierig empfunden werden: Dem Seitengespräch und der Einstellung der Studierenden "Gruppenarbeit bringt doch eh‘ nichts"

Konjunkturschlaglicht: Revision der EZB-Strategie?

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Influence of light and nutrient conditions on seedling growth of native and invasive trees in the Seychelles

Several recent studies have shown that plant invasions can occur in resource-poor and relatively undisturbed habitats. It is, therefore, important to investigate whether and how life-history traits of species invasive in such habitats differ from those of species that are only invasive in disturbed and resource rich habitats. We compared the growth of seedlings of native and invasive tree species from nutrient-poor secondary forests in the tropical Seychelles. We hypothesised that the relative performance of the two groups would change predictably along resource gradients, with native species performing better at low levels of resource availability and invasive species performing better at higher levels. To test this hypothesis, we performed a common garden experiment using seedlings of six invasive and seven native tree species grown under three levels of light (65, 11 and 3.5% of ambient light) and two of nutrients (low and high). Due to large variation among species, differences in growth rates (RGR) were not significant among seedlings of the native and the invasive species. However, seedlings of the invasive species showed higher specific leaf areas (SLA) and higher leaf nutrient contents than seedlings of the native species. They also exhibited greater plasticity in biomass and nutrient allocation (i.e., greater plasticity in LAR, RSR and leaf nutrient contents) in response to varying resource availability. However, differences between the mean values of these parameters were generally small compared with variation within groups. We conclude that successful invaders on nutrient-poor soils in the Seychelles are either stress-tolerant, possessing growth traits similar to those of the native species, or fast-growing but adapted to nutrient-poor soils. In contrast, the more typical, fast-growing alien species with no particular adaptations to nutrient-poor soils seem to be restricted to relative nutrient-rich sites in the lowlands. The finding—that some introduced species thrive in resource-poor habitats—suggests that undisturbed habitats with low resource availability may be less resistant to plant invasions than was previously suppose

Between skills and knowledge? On the meaning of science of education and pedagogical practice in teacher training

Die "Transformation" theoretischen Wissens in praktisches Können ist bereits in der Ausbildung anzuleiten. Die Wissensverwendungsforschung zeigt Ansätze auf, nach denen wissenschaftliches Wissen in der Lehrerbildung so entwickelt werden kann, dass es für professionelles Handeln und dessen Reflexion bedeutsam wird. (DIPF/Orig.) Anmerkungen zu diesem Beitrag von Andreas von Prondczynsky auf S. 423-424The question of how scientific knowledge can be made practically significant has a central meaning in the training of teachers. The transformation of theoretical knowledge into practical abilities has to be already introduced during academic education. The discussions of research on knowledge utilization points to some of the consequences for teacher education. (DIPF/Orig.

Cognitive defusion and guided imagery tasks reduce naturalistic food cravings and consumption: A field study

© 2018 Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0/ This author accepted manuscript is made available following 24 month embargo from date of publication (May 2018) in accordance with the publisher’s archiving policyThe present study investigated the effect of two craving reduction techniques, namely, cognitive defusion and guided imagery, on naturalistic food cravings. These techniques targeted the intrusion and elaboration stages of the craving process, respectively (Kavanagh, Andrade, & May, 2005). Participants underwent a seven-day baseline period followed by a seven-day intervention period, during which they recorded their food cravings as they occurred using online diaries accessed via smartphone. In the intervention period, participants were randomly assigned to one of cognitive defusion, guided imagery or control conditions. Participants in the cognitive defusion and guided imagery conditions listened to three-minute audio clips containing their respective instructions every time they experienced a food craving, and rated their craving intensity before and after the intervention, while the control participants recorded their cravings as they did in the baseline week. Results showed that both cognitive defusion and guided imagery techniques reduced craving frequency, intensity, the likelihood of consumption following cravings, and craving-related calorie intake, consistent with predictions. These findings show that cognitive defusion and guided imagery are useful for dealing with naturally occurring cravings across a range of foods, and can reduce craving-related consumption in everyday life

A re-analysis of NH4+ sorption on biochar: Have expectations been too high?

Sorption of nutrients such as NH4+ is often quoted as a critical property of biochar, explaining its value as a soil amendment and a filter material. However, published values for NH4+ sorption to biochar vary by more than 3 orders of magnitude, without consensus as to the source of this variability. This lack of understanding greatly limits our ability to use quantitative sorption measurements towards product design. Here, our objective was to conduct a quantitative analysis of the sources of variability, and infer which biochar traits are more favourable to high sorption capacity. To do so, we conducted a standardized remodelling exercise of published batch sorption studies using Langmuir sorption isotherm. We excluded studies presenting datasets that either could not be reconciled with the standard Langmuir sorption isotherm or generated clear outliers. Our analysis indicates that the magnitude of sorption capacity of unmodified biochar for NH4+ is lower than previously reported, with a median of 4.2 mg NH4+ g−1 and a maximum reported sorption capacity of 22.8 mg NH4+ g−1. Activation resulted in a significant relative improvement in sorption capacity, but absolute improvements remain modest, with a maximum reported sorption of 27.56 mg NH4+ g−1 for an activated biochar. Methodology appeared to substantially impact sorption estimates, especially practices such as pH control of batch sorption solution and ash removal. Our results highlight some significant challenges in the quantification of NH4+ sorption by biochar and our curated data set provides a potentially valuable scale against which future estimates can be assessed.publishedVersio