1,720,956 research outputs found
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
A preliminary investigation into the genetic variation and population structure of Taenia hydatigena from Sardinia, Italy
No full textCysticercosis caused by the metacestode stage of Taenia hydatigena is endemic in Sardinia. Information on the genetic variation of this parasite is important for epidemiological studies and implementation of control programs. Using two mitochondrial genes, the cytochrome c oxidase subunit 1 (cox1) and the NADH dehydrogenase subunit 1 (ND1) we investigated the genetic variation and population structure of Cysticercus tenuicollis from Sardinian intermediate hosts and compared it to that from other hosts from various geographical regions.The parsimony cox1 network analysis indicated the existence of a common lineage for T. hydatigena and the overall diversity and neutrality indices indicated demographic expansion. Using the cox1 sequences, low pairwise fixation index (Fst) values were recorded for Sardinian, Iranian and Palestinian sheep C. tenuicollis which suggested the absence of genetic differentiation.Using the ND1 sequences, C. tenuicollis from Sardinian sheep appeared to be differentiated from those of goat and pig origin. In addition, goat C. tenuicollis were genetically different from adult T. hydatigena as indicated by the statistically significant Fst value. Our results are consistent with biochemical and morphological studies that suggest the existence of variants of T. hydatigena
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
The Role of Ecology and Molecular Evolution in Shaping Global Terrestrial Diversity
No full textThe density of species varies widely across the earth. Most broad taxonomic groups have similar spatial diversity patterns, with greatest densities of species in wet, tropical environments. Although evidently correlated with climate, determining the causes of such diversity differences is complicated by myriad factors: many possible mechanisms exist to link climate and diversity, these mechanisms are not mutually exclusive, and they may overlap in the patterns they generate. Further, the importance of different mechanisms may vary between spatial scales. Generating uneven spatial diversity patterns in regions that are below equilibrium species richness requires either geometric or historical area effects, or regional differences in net diversification. Here, I investigate the global climate correlates of diversity in plants and vertebrates, and hypotheses that could link these correlates to net diversification processes, in particular through climate-linked patterns of molecular evolution. I first show strong climate–diversity relationships only emerge at large scales, and that the specific correlates of diversity differ between plants and animals. For plants, the strongest large-scale predictor of species richness is net primary productivity, which reflects the water–energy balance at large scales. For animals, temperature seasonality is the strongest large-scale predictor of diversity. Then, using two clades of New World passerine birds that together comprise 20% of global avian diversity, I investigate whether rates and patterns of molecular evolution can be linked to diversification processes that could cause spatial diversity patterns in birds. I find that most substitution rate variation between phylogenetically independent comparisons of avian sister species appears to result from mutation rate variation that is uncorrelated with climate. I provide evidence of nearly neutral effects in mitochondrial coding sequences, finding a significant, negative correlation between non-synonymous substitution rates and population size. Using phylogenetically independent comparisons, I also find that birds in low temperature seasonality, and isothermal environments, and birds with small elevational ranges have increased non-synonymous substitution rates, indicative of relaxed purifying selection. Other climate variables have no direct effect on molecular evolution. Molecular evolutionary patterns are dominated by mutation rate variation. Recovered patterns were stronger when mutation rate variation was controlled, indicating that such variation is a source of noise in analyses, and may be generally problematic across short genetic distances for analyses using mitochondrial genes. I bring these findings together with emerging literature to outline a framework for understanding net diversification patterns. Maintaining adaptations to climate, and the limits of those adaptations have population-genetic consequences that can affect lineage persistence and the processes of speciation and extinction in a fashion that is consistent with observations at multiple levels of diversity
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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