1,721,018 research outputs found
Ein Beitrag zur Moortypologie am sudlichen Rand des Sphagnum-Moorareals in Europa.
No full textThe vegetation of a well preserved mire in the southern Alps (South Tyrol) was studied and the results were correlated with data concerning hydrology, hydrochemistry and peat chemistry. The different vegetation types showed different nutrient levels both in the water and in the peat. In the hollows, nutrient concentrations were low in the water and higher in the peat. A reverse trend was observed in hummocks. Different patterns of accumulation and removal of mineral elements were observed along the peat profile: concentrations of N and P increase with depth; concentrations of Na, K, Mg and Mn decrease with depth; Fe and Al accumulate in the zone of water-table fluctuation. Two different areas could be distinguished within the mire, based on surface morphology, hydrochemistry and peat chemistry, viz. a peripheral area moderately rich in nutrients and a central area poor in nutrients. The mire cannot be typified as a true bog although the vegetation in its central area has several traits..
Seasonal chemistry of pore water in hummocks and hollows in a poor mire in the southern Alps (Italy)
No full textWe compared the seasonal patterns of sodium, potassium, calcium, and magnesium concentrations, pH, and electrical conductivity in pore water in a nutrient-poor mire of the southern Alps to precipitation chemistry, water-table depth, and potential evapotranspiration, with the main objective to unravel differences between pore-water chemistry in hummock and hollow habitats. Sodium concentrations in mire water were primarily determined by precipitation inputs, with highest values in spring. Potassium concentrations were dependent on vegetation uptake, peaking before the growing season started, and showing lowest values in summer. Calcium and magnesium concentrations were highest in summer. Cation-exchange processes, evaporation, and humification affected the periodicity of bivalent cations. The pH decreased from spring to autumn, gradually in hollow water and more abruptly in hummock water. Electrical conductivity followed the bivalent cation concentration pattern both in hummocks and hollows
Quellen und Bäche mit Blockgletschereinfluss
Full text linkFor this project running waters with and without
influence of rockglaciers were studied. Various
chemical and physical parameters, benthic fauna
and diatoms were analysed. Running waters
influenced by rockglaciers present low water
temperature, high conductivity levels, high concentrations
of sulphate, magnesium and calcium
and often also high levels of metals. Diversity
and abundance of aquatic organisms (macro and
meiobenthic fauna and diatoms) in the stretches
of water affected by rockglaciers are clearly lower
than in reference stretches of water unaffected
by them. The macrobenthical fauna in running
waters influenced by rockglaciers is very similar
to the fauna of running waters fed by glaciers. The
most common taxa are larvae of chironomids of
the subfamilies of Diamesinae and Orthocladiinae.
The high levels of metals represente a clear
limiting factor for the macrozoobenthos. In most
of the running waters analysed oligotraphentic
diatoms dominate.
Despite the high concentration of heavy metals
no teratological forms were found. Apart from the
chemical factors also the geographical position of
the sampling points influences the differences in
the diatom species composition
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Le diatomee dell'Alto Adige: qualità biologica dei corsi d'acqua e specie di particolare interesse scientifico
No full text- …
