1,720,962 research outputs found

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

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    “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

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    We 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

    Elevated testosterone levels during moult have contrasting effects on structural and carotenoid-based plumage colours in Eurasian Blue Tits

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    Feather colours can be produced by the organization of feather microstructure, by pigmentation (mainly due to melanins and carotenoids) or both. The expression of feather colours is usually influenced by testosterone (T) levels through several interacting mechanisms. First, high T levels can negatively affect bird condition and hence the expression of condition-dependent feather colours (e.g. carotenoid-based colours). Secondly, high levels of T can slow moult progression, which in turn may result in brighter colours, as moult speed has been shown to be negatively correlated with the expression of feather colours. Thirdly, T can affect the bioavailability of pigments that are involved in feather colours. The effect of experimental manipulation of T levels may therefore influence, either positively or negatively, feather colour expression according to the relative importance of these mechanisms and the type of coloration involved. We experimentally investigated whether plumage coloration is affected by T in yearling Eurasian Blue Tits Cyanistes caeruleus. We implanted 11 males and 11 females with T (T-birds) at the onset of their post-juvenile moult and compared the spectral reflectance of their structural ultraviolet (UV)/blue colour (crown feathers and upper lesser wing-coverts) and carotenoid-based yellow colour (breast feathers) with those of control birds (C-birds) that were sham-implanted (12 males, 16 females). At the implant date, all the right lesser wing-coverts were plucked in both experimental groups to test the effect of T on feathers grown exclusively during our treatment. After 40 days, the implants were removed. Two weeks before removing the implants, the mean T plasma levels were assayed (average 3.21 ng/mL in T-birds and 0.33 ng/mL in C-birds). In T-birds, body moult progression was suspended, and moult was resumed 33 days after implant removal. Moult duration from implant date, excluding suspension, did not differ between treatments and controls. T had a negative effect on UV coloration only in plumage that started growing exclusively during the treatment (right lesser wing-coverts), and not in other UV/blue plumage. In contrast, the carotenoid-based yellow coloration of the breast increased in T-birds, suggesting an immediate effect of T on the mobilization of carotenoids available for ornamentation. Despite sexual dichromatism, T treatment had similar effects in the two sexes. Our results highlight the importance of considering the effect of T on moult speed and possibly moult suspension in the interpretation of the results of studies based on T manipulation

    Sex-dependent response of primary moult to simulated time constraints in the rock sparrow Petronia petronia

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    There is growing evidence that moult speed affects plumage quality. In many bird species, males and females differ in terms of breeding effort, survival expectation and the relationship between fitness and plumage quality. Consequently, differences in moult strategies between the sexes can be expected. The aim of this study was to assess whether, under simulated time constraints and with no parental investment in the previous breeding season, males and females differed in: a) timing and duration of primary moult, b) growth rates of individual primary feathers, and c) number of concurrently growing feathers. We investigated the effect of time constraints generated by a treatment consisting of two decreasing photoperiods (slow changing photoperiod, SCP=2 min day-1 and fast changing photoperiod, FCP=8 min day-1) on the primary post-nuptial moult of captive rock sparrows Petronia petronia. Females started to moult on average 14 and 15 days later than males in both experimental groups. Primary moult duration was 10 (FCP) and 24 (SCP) days longer in males than in females, and, within sex, 34 (females) and 48 (males) days longer in SCP birds than in FCP ones. Females renewed a larger number of primaries simultaneously (5.7% in FCP and 12.8% in SCP) and had a higher total daily feather mass grown (9.9% in FCP and 22.4% in SCP), even though daily growth rates of individual primaries did not differ between sexes. As a result, males and females completed their primary moult at the same time within treatment. The observed differences in timing, duration and energy allocation for primary moult between the sexes probably have a genetic basis, as birds did not engage in reproduction during the preceding breeding seaso

    Dispelling the Myths Behind First-author Citation Counts

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    We 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

    Author Index

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    koamabayili/VECTRON-author-checklist: VECTRON author checklist

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    We 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
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