1,720,970 research outputs found
Analysis of historical and recent Ross Sea (Antarctica) molluscs datasets: benchmarking of existing knowledge to assess future changes
No full textIn polar areas, where the structure of marine communities and biodiversity are potentially threatened by climate-driven changes, it is really important to count on the availability of historical datasets to analyse the species diversity and distribution patterns with the final aim of creating a reference baseline to measure any possible change in the future. Historical dataset, in general, offer the widest geographical coverage for any give area and, very often, contains sampling stations that have never been re-sampled, standing as the unique source of information for a given site.
In Antarctica, as well as in many other areas, molluscs are one of the best-studied taxa, especially because they have a carbonate structure, which allow the classification even in the case where the body is found dead (Linse et al., 2006). In fact, all past Antarctic expeditions collected mollusc samples and this group, therefore, is a very good candidate to investigate and understand trends and patterns of marine biodiversity in the Southern Ocean.
Aim of this thesis is the creation of a complete dataset about all distributional data about Mollusca for the Ross Sea by combining the SOMBASE, a very large dataset includes information about several historical expeditions that occurred between the 1898 and 1968, and several datasets from other recent expeditions that have been made available from different sources. This new large dataset spans for over 100 years of samples and includes more than 700 discrete sampling events and it will be used to assess the robustness of our knowledge baseline about Antarctic molluscs diversity and distribution in the Ross Sea.
In particular, the thesis aims at modelling Ross Sea molluscs’ species richness as function of different environmental variables (e.g. depth, temperature, etc.) as well as of different sampling gears. All the above analyses will be performed by using appropriate statistical analyses such as Generalized Linear Model (GLM), Generalized Linear Mixed Model (GLMM), extrapolation and rarefaction techniques, in order to disclose all the possible information contained in the dataset.
Overall, the information achievable by analysing this dataset is of relevance in establishing a robust reference baseline to measure any future change in molluscs’ diversity, richness and distribution in this region. Moreover, these results will help determining, in the future, where are the areas with sampling gaps to be filled and the most useful sampling gears to be used
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
First record of living Acesta (Mollusca: Bivalvia) from an Antarctic seamount
No full textDuring a survey of Scott and Admiralty seamounts as part of the New Zealand IPY-CAML expedition in
2008, a number of new records and new species were documented (e.g., Bowden et al. 2011). Here we report on the finding of a single living specimen of Acesta sp. (station 207, Scott B seamount) and several loose valves, both recent and subfossil at seafloor photographic stations 198, 202, 207 (Scott B seamount), 219 (Scott A seamount) and of a single valve at epibenthic sled station 256 (Scott I seamount) (Fig. 1)
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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