1,721,067 research outputs found
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
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Habitat disturbance has subtle effects on pollinators and pollen quantity in the threatened self-incompatible plant Physaria filiformis (Brassicaceae)
Full text linkHabitat disturbance is widely considered to be a primary driver of global plant diversity losses. The consequences of habitat disturbance are likely to negatively impact reproductive success via disrupting plant-pollinator interactions, especially in species that are obligately outcrossing and therefore reliant upon pollination to produce offspring. To directly test the effects of plant-pollinator disruption on reproductive success, researchers often quantify pollen limitation (PL) of seed production. Studies quantifying PL have historically relied on hand pollination supplementation experiments, but these may confound estimates of effect sizes in three ways: first, by not accounting for resource reallocation, second, via introducing biases through extensive floral manipulation, and thirdly, by failing to disentangle quantitative and qualitative aspects of pollen limitation. To avoid these potential sources of bias, we described the functional relationship between pollen load and the success of pollen grains using a recently developed regression approach in two populations (Bois D'Arc and Rocky Barrens) with both disturbed and undisturbed habitat in P. filiformis (Brassicaceae), a threatened, self-incompatible plant species. Comparison of open and experimentally bagged flowers revealed low rates of autogamous self-pollination and pollen tube deposition, consistent with the existence of a functional self-incompatibility system. Second, disturbance had simultaneous, negative effects on both pollinator abundance and mean pollen loads in Bois D'Arc, yet these responses were not observed in the Rocky Barrens population. Third, our regression analysis revealed a subtle effect of disturbance on pollen quantity in Rocky Barrens, and there were no differences in pollen quality between disturbed and undisturbed sites in either population. These results add to the growing body of evidence that habitat disturbance negatively impacts plant-pollinator interactions, and illuminates some of the inferential, conceptual, and experimental biases inherent to traditional studies of PL in natural population
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
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Reproductive character displacement shapes a spatially structured petal color polymorphism in Leavenworthia stylosa
Full text linkCharacter displacement, or selection to reduce costly interspecific interactions, is a potentially important force driving trait evolution and the diversification of species. Floral traits may experience character displacement if they relax pollinator-mediated competition (ecological character displacement) or prohibit the formation of hybrids with reduced fitness (reproductive character displacement). We test these and alternative hypotheses to explain a yellow-white petal color polymorphism in Leavenworthia stylosa, where yellow morphs are spatially associated with a white-petaled congener (L. exigua) that produces hybrids with complete pollen sterility. A reciprocal transplant experiment rejected the hypothesis of local adaptation of color morphs, and a pollen limitation experiment showed that yellow petals do not alleviate competition for pollination. Pollinator observations revealed that Leavenworthia attracts a variety of pollinators that generally favor white petals and exhibit color constancy. Pollinator movements between species were infrequent and low maximum likelihood estimates of hybridization rates (~0.45% - 0.97%) were found in pooled DNA in each morph. Consistent with patterns of pollinator movement, hybridization rates were significantly higher in white morphs of L. stylosa, yielding a selection coefficient of s = 0.005 against this phenotype in sympatry with L. exigua. These v results provide support for reproductive character displacement as a mechanism contributing to the pattern of petal color polymorphism in L. stylosa
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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