1,720,965 research outputs found
Introduction to the Special Issue
No full textThis Special Issue contains 13 papers, at least 7 of
which are mainly based on results obtained during the
CRENODAT Project. Most papers deal with the biodiversity
and community ecology of a variety of autotrophic
and heterotrophic, macroscopic and microscopic
groups of organisms. Several evaluate the relative
importance of morphological (from microhabitat to
large scale), physical, and chemical factors in determining
community composition and structure. Some
discuss the conservation implications of the observed
patterns. One even applies palaeolimnological techniques
to a crenic habitat, showing the effects of land
use and management practices around the spring-head.
Spatial and temporal changes (from seasonal to long-term)
are also considered
Crenic habitats, hotspots for freshwater biodiversity conservation: Toward an understanding of their ecology
No full textSprings are unique aquatic habitats that contribute significantly to local and regional biodiversity because of their high habitat complexity and the large number of different spring types. Many springs are small, but they are numerous and often of high water quality, and thus, provide habitats for species that are rare elsewhere because of their sensitivity to anthropogenic impacts (least-impaired habitat relicts). Springs are often species-rich and contain a larger number of Red List taxa than other aquatic habitats. Hydrological factors, particularly flow permanence, water chemistry, and temperature are important ecological factors determining species distribution and community composition. Despite their importance for biodiversity and water quality, springs are much less studied than other aquatic ecosystems. They also are insufficiently covered by protective legislation, often resulting in the destruction of their natural habitat. The authors of papers in this special issue describe specific spring biota, including multitaxon studies, and discuss the role of environmental factors, habitat variability at different spatial and temporal scales, and the importance of natural and anthropogenic disturbance in spring habitats. They suggest directions for future research, including defining reference conditions for springs and their role in long-term ecological research, the development of quality-assessment methods, and their more sustainable use as freshwater resources. © 2012 The Society for Freshwater Science
Cocconeis intermedia peragallo & héribaud (Bacillariophyta): New information on morphology, distribution and ecology of a poorly known diatom species
No full textCocconeis intermedia was originally described by Peragallo & Héribaud in Héribaud (1893) as a fossil diatom species from samples collected in the Puy-de-Dôme department, Auvergne-Rhône-Alpes region (France). After the first brief description, the species was mostly mentioned as C. placentula var. intermedia in classic floristic books and, over time, it was reported living in a wide variety of aquatic environments. Despite this, the morphological features of C. intermedia remained poorly known: detailed information and micrographs are not available in the literature and the fine structure was never investigated. A Cocconeis species found in the thermomineral spring San Saturnino in Sardinia (Italy) was identified as Cocconeis intermedia Peragallo & Héribaud after an extensive literature search and a comparison with specimens from slides of Tempère & Peragallo collection housed in the Natural History Museum (London, United Kingdom). In this study we provide an amended description of the species with new morphological details as observed in light and scanning electron microscopy. We also provide additional information on the seasonal distribution and occurrence of the species on a variety of substrata in its habitat in Sardinia
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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