1,721,038 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
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
Diversity-oriented synthesis of novel heterocyclic compounds and their preliminary evaluation as antimalarial agents
No full textPush-pull alkenes refer to substituted alkenes bearing one or two electron-donating groups at one end of the double bond and one or two electron-accepting groups at the other end. These chemical properties make push-pull alkenes particularly reactive with electrophilic and nucleophilic species and therefore they have been widely used as building blocks in organic synthesis, especially for the preparation of heterocycle derivatives. In particular, ketene N,S- and S,S-acetals are the most representative class of push-pull alkenes used in organic synthesis. Recently, we reported a stepwise synthetic procedure through ketene N,S-acetal intermediates for the preparation of novel 5-anilinopyrazoles 1 endowed with antimalarial activities. To further extend the SARs of this class of compounds, we designed and synthesized a new series of 5-aminopyrazoles and 4-aminopyrimidines (derivatives 2 and 3) bearing all the structural determinants for the antimalarial activity. The unreported molecules were synthesized trough a versatile synthetic procedure which involved subsequent isolation of ketene S,S-acetals A and N,S-acetals B that were then cyclized with hydrazine or guanidine to afford the desired compounds. All the new isolated derivatives were screened against D10 and W2 Plasmodium strains and their cytotoxicity was evaluated on normal fibroblast cells by MTT assay
Synthesis and Antiplasmodial Activity of Bicyclic Dioxanes as Simplified Dihydroplakortin Analogues
No full textDispelling 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
Antiprotozoal Activity of Highly Substituted Pyrazole and Pyrimidine Derivatives
No full textTo further extend the structure-activity relationships of previously reported antimalarial anilino-pyrazoles VI, trisubstituted pyrazoles 13–15, and pyrimidines 16 and 17 are designed and synthesized. The novel derivatives are prepared thorough a divergent, chemo-selective approach starting from N,S-acetal intermediates. Compounds 13–17 are tested for their antimalarial and antileishmanial activity and their cytotoxicity is evaluated against human fibroblast. Pyrazoles 14 d,e and pyrimidine 17e are identified as novel and effective antiplasmodial agents being able to inhibit, at micromolar concentrations, chloroquine(CQ)-sensitive and CQ-resistant Plasmodium falciparum strains, as well as Leishmania infatum and Leishmania tropica protozoa. Additionally, favorable pharmacokinetics and toxicity profiles are predicted for the compounds
STRUCTURAL FUNCTIONALIZATION OF TRI-SUBSTITUTED PYRAZOLE DERIVATIVES AND PRELIMINARY EVALUATION OF THEIR ANTIMALARIAL ACTIVITY
No full textThe increasing prevalence of drug-resistant Plasmodium falciparum strains led to an urgent priority in the development of new antimalarial drugs. In this scenario, several pyrazole derivatives have been reported as antimalarial agents in the last years. Recently, novel Tri- and Tetrasubstituted pyrazole derivatives showed interesting antimalarial properties being endowed with micromolar IC50 values against Chloroquine (CQ)-sensitive D10 and CQ-resistant W2 Plasmodium strains. To further extend the structure activity relationships around these promising compounds, we designed and synthesized a new series of 3-phenyl-4-cyano pyrazoles bearing different basic chains at position 5. Briefly, the novel derivatives were prepared by sequentially reacting benzoylacetonitrile with carbon disulfide and iodomethane in the presence of sodium hydride. The so obtained thioketal A was substituted with the proper amine, leading to the formation of intermediates B, that were cyclized with hydrazine to afford the desired pyrazoles. All the newly isolated compounds were tested against D10 and W2 Plasmodium strains and their cytotoxicity was evaluated on normal fibroblast cells. Interestingly, the novel pyrazoles 2 showed micromolar IC50 values especially against CQ resistant W2 strain, resulting more effective than their analogues 1. Additionally, in preliminary tests the novel derivatives did not show any significant cytotoxicity on fibroblast cell lin
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