1,721,013 research outputs found
Communautés de diatomées des rivières de haute altitude sur substrats calcaire et siliceux (Trentino, Italie)
No full textRuolo delle diatomee nell'applicazione della direttiva europea quadro sulle acque
No full textNell’ambito della Direttiva Europea Quadro 2000/60/CE, ai fini della valutazione della qualità dei corsi d’acqua, devono essere utilizzati gli elementi biologici che, oltre alla comunità dei macroinvertebrati e alla fauna ittica, comprendono la composizione e abbondanza della flora acquatica. Le Diatomee, in particolare, oltre a rappresentare la componente principale della biomassa bentonica dei corsi d’acqua, sono ormai riconosciute a livello mondiale come ottimi bioindicatori e possono pertanto rappresentare una comunità di riferimento per lo studio della componente vegetale acquatica. In numerosi paesi europei sono già stati sviluppati metodi biologici di valutazione basati sulle Diatomee e, in alcuni di essi (es. Francia, Spagna), tali metodiche sono già state integrate nei sistemi di valutazione della qualità che prevedono campagne di campionamento annuali
sul reticolo idrografico. La Direttiva in particolare, richiede di definire le condizioni di riferimento in ogni tipo di corpo idrico nelle differenti ecoregioni, al fine di poter valutare l’eventuale scostamento tra lo stato osservato ed il corrispondente stato atteso. A tutt’oggi
nessuno degli indici diatomici esistenti è strutturato secondo tale principio: sarà pertanto necessario un lavoro di adattamento ai requisiti della Direttiva Quadro sulle acqu
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
Factors triggering the occurence and excessive development of Mougeotia spp. in large lakes
No full textDuring the last decades the filamentous green alga, Mougeotia spp. has been giving important contributions to the phytoplankton of some large peri-alpine lakes (Lake Geneva, Lake Garda, Lake Maggiore) and also in subtropical Lake Kinneret. Excessive Mougeotia blooms have been observed in these lakes but with different frequencies and intensities. While Lake Maggiore and Lake Kinneret were affected only a few years, Lake Geneva and Lake Garda displayed regular blooms. Besides the ecological consequences, these blooms cause practical problems in professional fishing. Mougeotia spp. has many features making it a good competitor; low sinking velocity, resistance to grazing, effective phosphorus uptake. In this study we focus on bottom-up environmental factors related to human activities, lake restoration processes or to global climate change that may trigger changes favouring development of Mougeotia sp
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
Distribution, écologie et expansion de Didymosphenia geminata dans le nord de l'Italie (Trentino)
No full textAppropriate 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
River biofilms sampling for both downstream DNA analysis and microscopic counts V.1
Full text linkThe objective of this protocol is to provide a reliable and replicable method for the
sampling of river micro-phytobenthos and associated microbes in biofilms, to be used
in both downstream DNA analysis and algal microscopic counts.
The filed protocol is optimized for routine sampling and is in agreement with CEN
guidance (NF EN 13946) and CEN technical report (CEN/TR 17245) for the analysis of
benthic diatoms from rivers and lakes.
The application proposed here in the context of EcoAlpsWater aims in comparing DNA
inventories to traditional inventories (microscopy).
This protocol is part of the deliverables provided by the WP1 of the Eco-AlpsWater
project. All members of the EcoAlpsWater consortium (involving 12 partners :
http://www.alpine-space.eu/projects/eco-alpswater/en/home) have contributed to
the optimization of this protocol
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
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