1,720,999 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
Spontaneous and induced aneuploidy in peripheral blood lymphocytes of patients with Alzheimer's disease.
No full textAbstract This study was aimed at assessing whether peripheral
blood lymphocytes of patients with Alzheimer’s
disease (AD) show significant levels of aneuploidy and
high percentages of cytogenetic events in vitro, indicating
a predisposition to aneuploidy spontaneously, or after
chemical treatment in vitro. A group of affected individuals
and a group of unaffected, age-, sex- and smokinghabit-
matched controls were identified. Lymphocytes were
cultured for analysis of the following cytogenetic parameters:
premature centromere division (PCD), satellite associations
of acrocentric chromosomes (SA) and micronuclei
(MN). In a subset of subjects, the fluorescence in situ
hybridization (FISH) technique was combined with the
MN assay, by means of a pancentromeric DNA probe for
the detection of the presence of centric material. To evaluate
the sensitivity to aneuploidogenic agents, in vitro
treatment of lymphocytes of affected individuals was performed
by adding griseofulvin, a chemical whose supposed
target is microtubule-associated protein(s). Both the
spontaneous frequency of MN and the frequency of PCD
was significantly higher in patient cells than in controls.
Furthermore, after application of the FISH technique, we
found that the majority of MN were composed of whole
chromosomes (because of the phenomenon of chromosome
loss). Metaphase analysis for the detection of associative
events between satellite regions of acrocentric
chromosomes showed no differences between the two
groups under study. Analysis of sensitivity to the aneuploidogen
griseofulvin showed that the patient group was
characterized by lower levels of MN induction compared
with controls. Our data confirm that peripheral blood lymphocytes
of AD patients are prone to undergo aneuploidy
spontaneously in vitro and support the hypothesis that microtubule
impairment might be associated with the disease
Pharmacokinetics and pharmacodynamics of levodopa afer acute and 6 week tolcapone administration in patients with parkinson's disease
No full textDispelling 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
Oxidative damage and cytogenic analysis in leukocytes of Parkinson's disease patients [4] (multiple letters) (Letter)
No full text- …
