1,721,169 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
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
FUNCTIONAL ANALYSIS OF THREE ARABIDOPSIS THALIANA ZIP GENES: ZIP4, ZIP6 AND ZIP9
No full textPlants have developed a variety of mechanisms to maintain the cellular concentration of essential metals within physiological limits. A complex homeostatic network controls the uptake, chelation and transport of metal ions to ensure healthy amounts of essential elements, and to avoid excess of non-essential ones (Williams and Salt, 2009). Metal transporters play a key role in metal uptake from the soil, metal homeostasis and metal transport across the cellular membranes. The ZIP (ZRT IRT1-like Proteins: Zinc-regulated transporter Iron-regulated transporter 1-like protein) family of metal transporter is involved in this complex network. Most members of the ZIP family fold into eight transmembrane domains with a variable metal-binding region, rich in histidine residues, between transmembrane domain III and IV (Guerinot, 2000). In Arabidopsis thaliana, 15 members of this family have been identified, and can be clustered in four main groups that share sequence similarity between 38 and 85%. To better understand the role of plant metal transporters, this project focuses on three ZIP proteins: AtZIP4, AtZIP6 and AtZIP9, for which limited information is available. AtZIP4 has been partially studied and the promoter analysis of this gene has been performed (Lin et al., 2016). Wintz et al. have shown that both ZIP4 and ZIP9, that share 77% similarity at the amino acid sequence, are up-regulated in roots and shoots of A. thaliana in Zn-deficiency conditions. On the contrary, AtZIP6, which doesn’t belong to any of the four groups mentioned above, does not show any modulation in expression at varying Zn or Fe concentrations. The promoter analysis for AtZIP6 and AtZIP9 has been performed on transgenic A. thaliana lines carrying the promoter sequence fused to the GUS reporter gene. The expression pattern of AtZIP6 and AtZIP9 showed different tissue localization. AtZIP9 expression is present in stomata in leaves, and localized in the root endodermis, cortex and epidermis, while AtZIP6 is expressed in the vascular tissues of both roots and shoots. Here, single AtZIP4, AtZIP6 and AtZIP9 knock-out mutant, zip4/zip9, zip4/zip6, zip6/zip9 double mutants and zip4/zip6/zip9 triple mutant obtained by crossing single homozygous mutant plants have been studied. The effect on growth of different Zn, Fe and Mn concentrations, and an ionomic analysis at different Zn concentrations, have been tested on these mutants looking for differences in the accumulation of multiple elements. To analyze the effect of the overexpression of ZIP4, ZIP6 and ZIP9, the coding sequences of the three genes have been cloned downstream of the strong promoter CaMV35S. The constructs were introduced into A. thaliana obtaining different over-expressing lines. Furthermore, the subcellular protein localization has been characterized in protoplasts transfected with genes encoding fusion proteins of ZIP4 and ZIP9 with GFP, and GFP observed at both the plasma membrane and tonoplast
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
Variable selection and specification of robust QSAR models from multicollinear data: arylpiperazinyl derivatives with affinity and selectivity for A2-adrenoceptors
No full textTwo QSAR models have been identified that predict the affinity and selectivity of arylpiperazinyl derivatives for alpha1 and alpha2 adrenoceptors (ARs). The models have been specified and validated using 108 compounds whose structures and inhibition constants (Ki) are available in the literature [Barbaro et al., J. Med. Chem., 44 (2001) 2118; Betti et al., J. Med. Chem., 45 (2002) 3603; Barbaro et al., Bioorg. Med. Chem., 10 (2002) 361; Betti et al., J. Med. Chem., 46 (2003) 3555]. One hundred and forty-seven predictors have been calculated using the Cerius 2 software available from Accelrys. This set of variables exhibited redundancy and severe multicollinearity, which had to be identified and removed as appropriate in order to obtain robust regression models free of inflated errors for the beta estimates - so-called bouncing betas. Those predictors that contained information relevant to the alpha2 response were identified on the basis of their pairwise linear correlations with affinity (-log Ki) for alpha2 adrenoceptors; the remaining variables were discarded. Subsequent variable selection made use of Factor Analysis (FA) and Unsupervised Variable Selection (UzFS). The data was divided into test and training sets using cluster analysis. These two sets were characterised by similar and consistent distributions of compounds in a high dimensional, but relevant predictor space. Multiple regression was then used to determine a subset of predictors from which to determine QSAR models for affinity to alpha2-ARs. Two multivariate procedures, Continuum Regression (the Portsmouth formulation) and Canonical Correlation Analysis (CCA), have been used to specify models for affinity and selectivity, respectively. Reasonable predictions were obtained using these in silico screening tools
- …
