1,721,003 research outputs found
Spermatozoan Morphology of 19 Species of Prosobranch Limpets (Patellogastropoda) with a Discussion of Patellid Relationships
No full textThe spermatozoon morphology of 19 species of Indo-Pacific, East Atlantic and Mediterranean patellid limpets was examined by transmission electron microscopy. All nine species of Patella and Helcion from the South Atlantic (southern Africa) and the Indo-Pacific, as well as three species from the North Atlantic, have sperm which correspond to one of the sperm groups I, II or III, previously described for patellacean limpets from southern Africa (Hodgson & Bernard 1988). With the exception of P. safiana and P. canescens, all 7 Patella species from the N.E. Atlantic/Mediterranean have sperm morphologies which closely resemble one another but are distinctly different from the sperm types of species in the southern hemisphere. These N.E. Atlantic/Mediterraean limpets have been assigned to a new sperm group, group VI. On the basis of sperm structure it is suggested that patellid limpets had three main centres of radiation: a N.E. Atlantic/Mediterranean centre; an East Atlantic centre with its focal point on the S.W. coast of southern Africa; an Indo-Pacific centre with its focal point on the S.E. coast of South Africa. Despite similarities between the species within groups, each has a unique sperm. An examination of spermatozoa of one patellid from Namibia and one from S. Angola (both initially identified as Patella miniata), has revealed that their sperm are distinctly different, as well being different from that of P. miniata from South Africa. Subsequently, the species from Namibia was identified as P. adansonii. Furthermore, P. cf. miniata from S. Angola had a sperm which is remarkably similar to that of P. safiana from N.W. Africa and the two may be conspecific
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
