1,720,959 research outputs found
Marine alien species in Western Cape harbours, South Africa: A tool for stategically focusing monitoring efforts
No full textIncludes bibliographical references.Alien species are the second most important cause for the loss in biodiversity globally, after habitat destruction. Marine alien species are transferred across the globe through various vectors, including ballast water, hull fouling, aquaculture facilities and the aquarium and pet trade. Ballast water has previously been considered as the primary vector of alien species transfer. However, fouling is becoming widely recognised as an important vector for the transfer of marine alien species both internationally, as well as in South Africa, where it has been reported to contribute 48% of marine species introductions. The objectives of this study were to document alien species from fouling assemblages in six South African harbours (St Helena Bay, Saldanha Bay, Table Bay, Hout Bay, Gansbaai and Mossel Bay) and to use the data collected to identify factors (such as vectors and other harbour characteristics and activities), that could be used by management authorities to target harbours upon which to focus monitoring efforts. This was done by taking subtidal scrape samples and visual samples from harbour walls and pillars. The prioritisation of harbours was obtained through the use of regression tree models utilising CART (Classification and Regression Trees)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Tracking the settlement patterns of marine biofouling communities
No full textften focus on surveying after a specific period of settlement, with few regions being
able to implement ongoing monitoring systems. Whilst these programs are beneficial,
they provide only a snapshot in time and may miss key information about the temporal
settlement patterns of alien fouling species and the associated management implications.
The current study initiated a temporal settlement study that could 1) track the settlement
patterns of fouling species with a focus on detecting alien species and 2) highlight
the change in community structure across different months, providing an insight
into the ecological succession. The study was conducted in a marina in Cape Town,
South Africa, using PVC settlement plates, and serves as a baseline for a longer term monitoring settlement study. The findings indicate that the species richness
and abundance differed significantly across the months (Wald test: p < 0.001), with
a rapid increase in both measures within a month and a gradual decline in species
richness after two to three months. A total of 12 alien species were detected accounting
for 55% of the community structure. Within the first month, eight of those species
had already settled. Overall, four species (Corella eumyota, Diplosoma listerianum,
Neodexiospira brasiliensis and Balanus trigonus) were particularly dominant
throughout the study. The ascidian, Corella eumyota currently listed as native, was
one of the first species to settle and demonstrated strong competitive traits, raising
concerns about its current status in the region. The findings highlight the value of
temporal settlement studies revealing patterns that may have been overlooked when
sampling at only one point in time. Thus, a longer-term monitoring program that
tracks the temporal settlement patterns of alien fouling species could start to provide
valuable insights to management authoritie
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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