Zum überfälligen Paradigmenwechsel in der Fremdsprachendidaktik

In letzter Zeit beschäft igt sich die angewandte kognitive Linguistik verstärkt mit Metaphorisierungsprozessen bei der Sprachverarbeitung. Dabei rückt zunehmend auch der Bereich der Grammatikvermittlung im Fremdsprachenerwerb in den Blick. Motiviert ist diese Forschung von der Einsicht, dass strukturelle Verfahren der Grammatikvermittlung auch bei noch so guter methodischer Aufmachung wenig Nachhaltigkeit erreichen, konzeptuelle Ansätze dagegen viel besser modulieren, was im natürlichen Spracherwerb oft so viel problemloser und schneller verläuft. Der Beitrag zeigt exemplarisch auf, was an einem konzeptuell-funktionalen Ansatz der Grammatikdarstellung das Innovative und Effi ziente ist und wie dies in geeigneter Weise in Grammatikanimationen umgesetzt werden kann. Ergebnisse erster empirischer Studien zur Nachhaltigkeit des gewählten Ansatzes untermauern seine Wirksamkeit. Der Beitrag gibt Impulse für weitere Forschungsprojekte genauso wie für die konkrete Arbeit in Unterricht und Spracherwerb. Er kann darüber hinaus als Baustein eines (längst überfälligen) Paradigmenwechsels in der Fremdsprachendidaktik gesehen werden.Recentemente la linguistica cognitiva applicata ha rivolto grande attenzione ai processi di metaforizzazione nell’elaborazione linguistica. Parallelamente è stato dedicato maggior interesse anche all’ambito dell’insegnamento grammaticale nell’apprendimento delle lingue straniere. Alla base di questo campo di studi vi è la constatazione che i processi di trasmissione grammaticale di tipo strutturale – anche laddove siano supportati da ottima presentazione metodologica – ottengono risultati di scarsa effi cacia, mentre approcci concettuali si rivelano in grado di modulare assai meglio quanto nella naturale acquisizione linguistica avviene spesso in modo molto più semplice e veloce. Il saggio esemplifi ca l’innovatività e l’effi cacia di un approccio concettuale-funzionale nella rappresentazione grammaticale e mostra come ciò possa essere realizzato in modo adeguato tramite animazioni grammaticali. I risultati dei primi studi empirici sull’effi cacia dell’approccio scelto ne confermano la validità. Il saggio fornisce impulsi per ulteriori prospettive di ricerca e per l’applicazione concreta in ambito didattico e nell’acquisizione linguistica. Lo si può inoltre considerare un ulteriore tassello nella direzione di un – non più rimandabile – cambio di prospettiva nella didattica delle lingue straniere

Italian reference rivers under the Water Framework Directive umbrella: do natural factors actually depict the observed nutrient conditions?

Abstract Background Despite the efforts made in the last century to counteract the nutrient enrichment from diffuse and point-sources, the excess of nitrogen and phosphorous is among the main causes of degradation of European rivers. In this context, determining natural background concentrations of nutrients in rivers is crucial for a correct definition of their ecological status. In the most anthropized regions, this is a difficult task. This study provides a nation-wide assessment of the nutrient concentration variability between Italian river reference sites. Results We applied the Affinity Propagation technique to identify groups of river sites classified as reference based on measured nutrients and oxygen water saturation. The role of natural and anthropogenic factors determining differences in nutrients concentration between groups of sites was explored. Nitrate concentrations varied from 0.01 mg N l−1 to more than 5 mg N l−1. Ammonia and total phosphorous varied between 0.001 and 0.12 mg l−1. Observed nutrient levels, although in line with those identified for reference sites in other countries, largely exceed the ranges reported for natural basins. Atmospheric deposition of inorganic N and artificial and/or high-impact agricultural land use are the major factors determining differences in nutrient concentration. Factors like, e.g. catchment size, precipitation amount and altitude do not play a relevant role in explaining nutrient differences between groups of reference sites. Conclusions We especially focused on (i) major causes of failure in the selection of appropriate reference sites in Italy; (ii) the potential of setting higher NO3-N thresholds for the classification of ecological status in specific areas, and (iii) the prospective of a regionalization approach, in which human effects are accepted to a low degree for reference site selection or when setting thresholds for peculiar geographical areas

The ratio of lentic to lotic habitat features strongly affects macroinvertebrate metrics used in southern Europe for ecological status classification

Abstract Biological quality in rivers based on benthic macroinvertebrates is typically assessed by comparison with expected reference conditions, which represent relatively undisturbed situations. Commonly, reference conditions are set in agreement with river typologies to handle major ecological differences and limit biological variability. Although natural hydrological variation can be highly influential, site-specific tuning of reference conditions is rare in Mediterranean countries. River flow and local hydraulics change continuously over time, shaping the occurrence of lentic and lotic habitat features. Thus, biological reference conditions might require site-specific adjustment based on the ratio of lentic to lotic habitats assessed at the time of sampling. This would help reducing systematic bias in ecological assessments, interpreting benthic invertebrate responses to pressures, and diminishing the amount of unexplained biological variability. In this study, the response to the lentic-lotic character of river reaches was assessed for nineteen macroinvertebrate metrics and indices commonly used for the classification of ecological status in South European rivers. The study sites, with a prevalent temporary character, were located in Sardinia, southwestern Italy. Most metrics were significantly related to the lentic-lotic habitat conditions, both in pool and riffle mesohabitats, and their response curves were either parabolic or linearly decreasing at increasing lentic conditions. Taxonomic richness, score-based metrics, ovoviviparous taxa and multi-metric indices related well to the lentic-lotic conditions, while abundance metrics correlated less. The potential impact on ecological status classification was tested for the method formally used in Italy, which had a major role in comparing and inter-calibrating European assessment methods for the Water Framework Directive. After adjusting for bias due to the ratio of lentic to lotic habitat features, quality classification shifted towards better ecological status for ≈ 23% samples. This highlighted the impact of ignoring lentic-lotic information when defining reference conditions for assessing ecological status, varying from difficulties in understanding the biological response to pressures, to largely biased ecological status classification. The observed response of macroinvertebrate metrics to lentic-lotic conditions should be a key consideration for realistic ecological status assessment and could further be a valuable input for evaluating the effects of human-induced hydrological alteration and for assessing environmental flows

High resolution spectroscopy to investigate impurities in YAB single crystals

The work explores the feasibility of high resolution (as fine as 0.02 cm-1) Fourier transform spectroscopy applied at 9 K in the 500-25000 cm-1 range to detect traces of unwanted impurities, mainly rare earths (RE3+) in crystals: the system chosen is YAl3(BO3)4 (YAB). Weak traces of RE3+ (Nd, Dy, Er, Tm, Yb), but also of Cr3+ and OH-, were successfully monitored by comparing the spectra of YAB samples under examination with those intentionally doped with a given ion. The analysis performed on a variety of samples shows how Cr3+, Nd3+, and Yb3+ are the most frequent unwanted dopants and can provide suggestions to the crystal growers about the performances of different crystal growth lines. According to a preliminary evaluation, the Er3+ traces detection limit is as low as 1-2x10-4 mol% in 1 cm thick samples. The advantages of the method, which is sample non-destructive, are discussed in comparison with those currently applied

High resolution x-ray characterization of mosaic crystals for hard x- and gamma-ray astronomy

For hard x-ray astronomy in the 70-1000 keV energy range Laue lenses have been proposed where the focusing elements are made of single mosaic crystals, in order to increase the diffraction efficiency with respect to perfect crystals. Suitable crystals to be used for such application should have a sufficient density to increase the diffraction efficiency and a mosaicity ranging between 30 arcsec and 1-2 arcmin, depending on the lens focusing distance and resolution. In the past germanium and copper crystals, often employed as monochromators for neutrons, have been considered. In this work we propose several crystalline materials of different degree of crystal perfection such as GaAs, Cu, CdTe, and CdZnTe as possible mosaic crystals for hard x-ray astronomy. They were analyzed by high resolution x-ray diffraction at 8 keV and by diffraction at energies up to 700 keV at synchrotron. It was found that: -CdTe and CdZnTe crystals exhibit low angle grain boundaries preventing the formation of a single diffracted x-ray beam; -Cu crystals exhibit mosaicity of the order of several arcmin, however a deep etching is needed to remove the cutting damage; -GaAs crystals grown by LEC method show mosaicity between 15 and 30 arcsec and good diffraction efficiency up to energies of 700 keV. Annealing and surface damage were considered as possible methods to increase the GaAs crystal mosaicity

Dynamic of nitrogen and dissolved organic carbon in an alpine forested catchment: atmospheric deposition and soil solution trends

A number of studies have reported decreasing trends of acidifying and N deposition inputs to forest areas throughout Europe and the USA in recent decades. There is a need to assess the responses of the ecosystem to declining atmospheric pollution by monitoring the variations of chemical species in the various compartments of the forest ecosystem on a long temporal scale. In this study, we report on patterns and trends in throughfall deposition concentrations of inorganic N, dissolved organic N (DON) and C (DOC) over a 20-year (1995–2015) period in the LTER site -Val Masino (1190 m a.s.l.), a spruce forest, in the Central Italian Alps. The same chemical species were studied in the litter floor leachates and mineral soil solution, at three different depths (15, 40 and 70 cm), over a 10-year period (2005–2015). Inorganic N concentration was drastically reduced as throughfall and litter floor leachates percolated through the topsoil, where the measured mean values (2 µeq L-1) were much lower than the critical limits established for coniferous stands (14 µeq L-1). The seasonal temperature dependence of throughfall DOC and DON concentration suggests that the microbial community living on the needles was the main source of dissolved organic matter. Most of DOC and DON infiltrating from the litter floor were retained in the mineral soil. The rainfall amount was the only climatic factor exerting a control on DOC and N compounds in throughfall and forest floor leachates over a decadal period. Concentration of SO4 and NO3 declined by 50% and 26% respectively in throughfall deposition. Trends of NO3 and SO4 in forest floor leachates and mineral soil solution mirrored declining depositions. No trends in both DON and DOC concentration and in DOC/DON ratio in soil solutions were observed. These outcomes suggest that the declining NO3 and SO4 atmospheric inputs did not influence the dynamic of DON and DOC in the Val Masino forest. The results of this study are particularly relevant, as they are based on a comprehensive survey of all the main compartments of the forest ecosystem. Moreover, this kind of long-term research has rarely been carried out in the Alpine region

A biological tool to assess flow connectivity in reference temporary streams from the Mediterranean Basin

Many streams in the Mediterranean Basin have temporary flow regimes. While timing for seasonal drought is predictable, they undergo strong inter-annual variability in flow intensity. This high hydrological variability and associated ecological responses challenge the ecological status assessment of temporary streams, particularly when setting reference conditions. This study examined the effects of flow connectivity in aquatic macroinvertebrates from seven reference temporary streams across the Mediterranean Basin where hydrological variability and flow conditions are well studied. We tested for the effect of flow cessation on two streamflow indices and on community composition, and, by performing random forest and classification tree analyses we identified important biological predictors for classifying the aquatic state either as flowing or disconnected pools. Flow cessation was critical for one of the streamflow indices studied and for community composition. Macroinvertebrate families found to be important for classifying the aquatic state were Hydrophilidae, Simuliidae, Hydropsychidae, Planorbiidae, Heptageniidae and Gerridae. For biological traits, trait categories associated to feeding habits, food, locomotion and substrate relation were the most important and provided more accurate predictions compared to taxonomy. A combination of selected metrics and associated thresholds based on the most important biological predictors (i.e. Bio-AS Tool) were proposed in order to assess the aquatic state in reference temporary streams, especially in the absence of hydrological data. Although further development is needed, the tool can be of particular interest for monitoring, restoration, and conservation purposes, representing an important step towards an adequate management of temporary rivers not only in the Mediterranean Basin but also in other regions vulnerable to the effects of climate change

Spatial scale effects on taxonomic and biological trait diversity of aquatic macroinvertebrates in Mediterranean streams

We examined the effect of spatial scale on aquatic macroinvertebrate communities in Mediterranean streams from six basins distributed across southern Europe, including Spain, France, Italy, and Greece. We classified the studied streams according to their long-term aquatic regime into the three following types: (i) permanent (P), (ii) intermittent with summer pools (I-P), and (iii) intermittent with summer dry channels (I-D). For each stream type, we analyzed taxonomic and trait diversity, as well as the composition of the macroinvertebrate community, following a spatially nested design at three spatial scales of analysis: microhabitat (substratum patches), mesohabitat (pools vs. riffles), and macrohabitat (streams). In order to assess intrinsic seasonal variability in streams from the Mediterranean region, 20 Surber samples were taken from each stream according to meso- and microhabitat frequency in the wet and the dry season during 2010. Given the need for adaptation to specific hydrological conditions and the fact that microhabitats should encompass the niche requirements of particular taxa, we hypothesized that this spatial scale would have a greater influence on macroinvertebrate taxa composition and biological traits than the other two larger spatial scales in intermittent streams. We observed that patterns in the relative importance of variance components across hierarchical spatial scales changed with time because low flow or droughts altered both mesohabitat preva - lence and microhabitat composition. Our results confirm the importance of the microhabitat scale in I-P streams in the wet season but not in the dry one, when a loss of microhabitat diversity occurred. Stream-to-stream variability was more important in P and I-D streams. Our study also explored the relationships between traits and aquatic regimes. We found that aquatic macroinvertebrates inhabiting permanent streams exhibited traits related to the longer duration of life cycles in these rivers (e.g. large size of adult stages) and adaptations to flowing conditions (e.g. modes of aquatic dispersal), whereas aquatic macroinvertebrates inhabiting intermittent streams with summer pools had traits adapted to depositional conditions and ecological preferences for confined habitats (i.e. disconnected pools without flow). Finally, aquatic macroinvertebrates from intermittent streams with summer dry channels had adaptations conferring ability to survive periods with no water (e.g. modes of aerial dispersal, resistant stages). These results indicate that microhabitat conditions should not be neglected as they can play an important role in certain situations