1,721,320 research outputs found
Bartoli (M.). Saggi di linguistica spaziale
No full textLeroy Maurice. Bartoli (M.). Saggi di linguistica spaziale. In: Revue belge de philologie et d'histoire, tome 26, fasc. 1-2, 1948. pp. 136-137
Seasonal variation of radial oxygen loss in Vallisneria spiralis L.: An adaptive response to sediment redox?
No full textIn temperate shallow aquatic bodies large seasonal variations in water temperature result in a wide range of benthic respiration rates which are coupled to changes of pore water redox. To cope with such sediment modifications, we hypothesize that rooted macrophytes vary the oxygen amount released by roots. To this purpose, we reinterpreted published data on seasonal oxygen and inorganic carbon fluxes measured in vegetated (Vallisneria spiralis L.) sediments by combining them with the outcomes from laboratory incubations of apical tips and intact plants.Results suggest that V. spiralis transfers progressively higher amounts of oxygen to roots in the shift winter-summer. Maximum radial oxygen loss occurs in early autumn and probably overlaps with the lowest sediment redox. At the end of the summer, the exhaustion of energy yielding electron acceptor pools is in fact coupled to input of labile organic matter from senescent meadows, further exacerbating the demand of oxidized compounds to support degradation processes. The oxygen released by roots measured in hydroponic conditions corresponds to ∼7% of the plant gross production in the light; a small amount of oxygen is leaked also in darkness. We speculate that the oxygen injected in the pore water by a V. spiralis meadow can significantly affect the sediment biogeochemistry of eutrophic sites, representing up to ∼20% of the daily benthic oxygen consumption. © 2012 Elsevier B.V
A perspective on bismuth based materials for the photodegradation of organic pollutants
Full text linkThe photoactive bismuth materials represent an interesting tool for facing the complexity represented by the organic contained wastewater streams and the engineering of their chemical and surface properties is the key to a solve the water pollution. In this review, we are discussing the use of bismuth based materials for photooxidative treatment of polluted water critically evaluating and highlighting the strengths and the weaknesses of the approach with a focus on the properties of the materials but reporting as well the currently available technologies providing an agile reference point in the field
Seasonal regulation of nitrification in a rooted macrophyte (Vallisneria spiralis L.) meadow under eutrophic conditions
No full textVariable oxygen release from the root of macrophytes growing in ammonium-rich organic substrates can stimulate the process of nitrification. To verify this hypothesis, we performed seasonal measurements of potential nitrification activity in sediments with and without the perennial submersed plant Vallisneria spiralis L. (Hydrocharitaceae). Pore water and sediment features were simultaneously considered in order to provide insights into the regulation of the process. Results demonstrated a significant effect of season and plant presence on potential nitrification activity, with higher rates in winter and lower rates in summer. Vegetated sediment displayed lower pore water ammonium, but always higher potential nitrification activity compared to the unvegetated substrate, regardless the season. Nitrification activity was strongly correlated with pore water redox status, which were affected by both season and plant presence. Along its annual cycle V. spiralis promoted more oxidized condit..
Analisi della diversità floristica in ambienti acquatici marginali del fiume Oglio sub lacuale (Italia settentrionale): la componente macrofitica
No full text
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
- …
