Bildungspolitik in Schieflage. Kritik am Lehrplan 21

Die schweizerische Bildungspolitik befindet sich in Schieflage. Es fehlen klare Konzepte, es fehlt eine klare Zielsetzung, es fehlt an politischem Konsens, es fehlt auch an fachlicher Kompetenz, und es fehlt vor allem eine klare Begründung für die vielen Reformen, die laufen und laufend neu initiiert werden.

Die Kamerabrillenmethode – eine erkenntnistheoretische Begründung

Beobachtung und Videografie haben eine lange Tradition in der psychologischen Forschung. In unseren Studien erfassen wir die Umwelten von aggressiven Jungen und Mädchen mit einer neu entwickelten Kamerabrillenmethode. Die Jugendlichen tragen die Brillen über ganze Tagesverläufe und registrieren so das Geschehen aus ihrer räumlichen Perspektive. Die Forschenden kodieren diese Aufnahmen am Computer. Im vorliegenden Artikel wird nun der methodische Neuansatz vor einem erkenntnistheoretischen Hintergrund kritisch reflektiert. Was geschieht eigentlich, wenn wir beobachten? Wie lässt sich der Erkenntnisprozess als mehrfache Reduktion und Konstruktion fassen? Inwieweit unterscheidet sich das Wahrnehmungsfeld der Brillentragenden und der Forschenden? Welche Gemeinsamkeiten und Unterschiede bestehen zwischen einer Kamerabrille und dem menschlichen Auge? Videografie verleitet zu der Annahme, Realität könne mit einer Kamera abgebildet werden. Erkenntnis entsteht jedoch in einem hoch reduktiven und konstruktiven Prozess der Welterzeugung. Aus verschiedenen Arten der Welterzeugung resultieren verschiedene Weltversionen. Dies darf aber keinesfalls als Aufforderung zur Beliebigkeit verstanden werden. Die erzeugten Versionen der Welt müssen den Kriterien der Viabilität und der Intersubjektivität genügen.

Are land sparing and land sharing real alternatives for European agricultural landscapes?

There is a lively debate on whether biodiversity conservation and agricultural production could be better reconciled by land sparing (strictly separating production fields and conservation areas) or by land sharing (combining both, agricultural production and biodiversity conservation on the same land). The debate originates from tropical countries, where agricultural land use continues to increase at the expense of natural ecosystems. But is it also relevant for Europe, where agriculture is withdrawing from marginal regions whilst farming of fertile lands continues to be intensified? Based on recent research on farmland biodiversity we conclude that the land sharing – land sparing dichotomy is too simplistic for Europe. Instead we differentiate between productive and marginal farmland. On productive farmland, semi-natural habitats are required to yield ecosystem services relevant for agriculture, to promote endangered farmland species which society wants to conserve even in intensively farmed regions, and to allow migration of non-farmland species through the agricultural matrix. On marginal farmland, high-nature value farming is a traditional way of land sharing, yielding high quality agricultural products and conserving specialized species. To conserve highly disturbance-sensitive species, there is a need for nature reserves. In conclusion, land sparing is not a viable olution for Europe in both productive and marginal farmland but because of different reasons in each type of farmland.

Effects of Habitat Fragmentation on Abundance, Larval Food and Parasitism of a Spider-Hunting Wasp.

Habitat fragmentation strongly affects species distribution and abundance. However, mechanisms underlying fragmentation effects often remain unresolved. Potential mechanisms are (1) reduced dispersal of a species or (2) altered species interactions in fragmented landscapes. We studied if abundance of the spider-hunting and cavity-nesting wasp Trypoxylon figulus Linnaeus (Hymenoptera: Crabronidae) is affected by fragmentation, and then tested for any effect of larval food (bottom up regulation) and parasitism (top down regulation). Trap nests of T. figulus were studied in 30 agricultural landscapes of the Swiss Plateau. The sites varied in the level of isolation from forest (adjacent, in the open landscape but connected, isolated) and in the amount of woody habitat (from 4 % to 74 %). We recorded wasp abundance (number of occupied reed tubes), determined parasitism of brood cells and analysed the diversity and abundance of spiders that were deposited as larval food. Abundances of T. figulus were negatively related to forest cover in the landscape. In addition, T. figulus abundances were highest at forest edges, reduced by 33.1% in connected sites and by 79.4% in isolated sites. The mean number of spiders per brood cell was lowest in isolated sites. Nevertheless, structural equation modelling revealed that this did not directly determine wasp abundance. Parasitism was neither related to the amount of woody habitat nor to isolation and did not change with host density. Therefore, our study showed that the abundance of T. figulus cannot be fully explained by the studied trophic interactions. Further factors, such as dispersal and habitat preference, seem to play a role in the population dynamics of this widespread secondary carnivore in agricultural landscapes.

Exposure of silver-nanoparticles and silver-ions to lung cells in vitro at the air-liquid interface

BACKGROUND: Due to its antibacterial properties, silver (Ag) has been used in more consumer products than any other nanomaterial so far. Despite the promising advantages posed by using Ag-nanoparticles (NPs), their interaction with mammalian systems is currently not fully understood. An exposure route via inhalation is of primary concern for humans in an occupational setting. Aim of this study was therefore to investigate the potential adverse effects of aerosolised Ag-NPs using a human epithelial airway barrier model composed of A549, monocyte derived macrophage and dendritic cells cultured in vitro at the air-liquid interface. Cell cultures were exposed to 20 nm citrate-coated Ag-NPs with a deposition of 30 and 278 ng/cm2 respectively and incubated for 4 h and 24 h. To elucidate whether any effects of Ag-NPs are due to ionic effects, Ag-Nitrate (AgNO3) solutions were aerosolised at the same molecular mass concentrations. RESULTS: Agglomerates of Ag-NPs were detected at 24 h post exposure in vesicular structures inside cells but the cellular integrity was not impaired upon Ag-NP exposures. Minimal cytotoxicity, by measuring the release of lactate dehydrogenase, could only be detected following a higher concentrated AgNO3-solution. A release of pro-inflammatory markers TNF-alpha and IL-8 was neither observed upon Ag-NP and AgNO3 exposures as well as was not affected when cells were pre-stimulated with lipopolysaccharide (LPS). Also, an induction of mRNA expression of TNF-alpha and IL-8, could only be observed for the highest AgNO3 concentration alone or even significantly increased when pre-stimulated with LPS after 4 h. However, this effect disappeared after 24 h. Furthermore, oxidative stress markers (HMOX-1, SOD-1) were expressed after 4 h in a concentration dependent manner following AgNO3 exposures only. CONCLUSIONS: With an experimental setup reflecting physiological exposure conditions in the human lung more realistic, the present study indicates that Ag-NPs do not cause adverse effects and cells were only sensitive to high Ag-ion concentrations. Chronic exposure scenarios however, are needed to reveal further insight into the fate of Ag-NPs after deposition and cell interactions.