1,721,001 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
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
Lack of prognostic significance of the monoclonal antibody Ki-S1, a novel marker of proliferative activity, in node-negative breast carcinoma
No full textIn a series of 205 node-negative breast cancers (NNBC), we determined staining by the novel antibody Ki-S1, a marker of tumor cell proliferation, in order to test its association with other prognostic variables and its prognostic significance. Ki-S1 was determined in routinely formalin-fixed paraffin-embedded tumor samples. Ki-S1 gave a nuclear staining in the majority of the carcinomas (188 of 205), with percentages of reacting nuclei ranging from 2% to 90% (median value of 7%). In 107 tumors frozen sections were available to also assess the Ki-67 antibody. Among these, 94 had a nuclear staining of cancer cells ranging from 5% to 80% (median value of 7%). In 46 tumors we also determined the MIB-1 antibody. The percentage of MIB-1 nuclear staining ranged from 1% to 50% (median value of 20%). There was no significant relationship between Ki-S1 and the other two cell kinetic markers. Ki-S1 labeling was significantly associated only with tumor size (p = 0.03). With a median follow-up of 6 years, Ki-S1 had no significant prognostic value for either relapse-free survival (RFS) or overall survival (OS) (Ki-S1 as continuous logarithmic variable; p = 0.86 and p = 0.23, respectively). For RFS the following variables had a significant prognostic value: Ki-67 ( 10%; p = 0.037); progesterone receptor (PgR) expression (- vs+/++; p = 0.041); tumor size (pT1 vs pT2-3; p = 0.042) and grading (GI vs GII-III; p = 0.047). For OS, tumor size (p = 0.0044), age (continuous variable; p = 0.0060), and Ki-67 (p = 0.043) were significantly prognostic. In multivariate analysis (final model), only tumor size retained a significant and independent prognostic value for RFS (p = 0.0042). For OS, both tumor size (p = 0.0029) and age ( 55 years; p = 0.041) retained significance in the multivariate model. In conclusion, Ki-S1 does not seem to have prognostic relevance in this series of NNBC. Possible hypotheses to explain this observation are discussed
p53 accumulation in ovarian carcinomas and its prognostic implications
No full textIntranuclear p53 accumulation is a common finding in many different human tumors and is associated with a worse prognosis in breast, colon, and lung carcinomas. We immunostained a series of common epithelial ovarian cancers to assess (1) the prevalence of p53 accumulation and its clinicopathologic correlations, and (2) its prognostic implications. The study population comprised 98 patients (83 with follow-up data). A variable degree of p53 immunoreactivity, strictly confined to the neoplastic cells, was detected in 54 tumors (55%). Among these tumors there were 10 low expressors (1% to 10% immunoreactive tumor cells), 16 moderate expressors (10% to 50% immunoreactive cells), and 28 high expressors (> 50% immunoreactive cells). The prevalence of p53 immunoreactivity did not show any association with the histologic type of the tumors or with the disease stage at presentation. p53 Accumulation, however, was significantly more prevalent among poorly differentiated tumors (P = .0059, by analysis of variance). Life table analysis demonstrated that patients with tumors showing moderate and high p53 expression had worse disease-free and adjusted lengths of survival (P = .0011 and P = .0025, respectively, by Mantel-Cox). The patients with "early stage" disease (stages I and II) and p53 accumulation showed a trend toward shorter length of survival, but this did not reach statistical significance. However, patients with "advanced stage" disease (stages III and IV) and moderate or high p53 accumulation had a poorer prognosis (P = .0154 and P = .0171, for disease-free and adjusted length of survival, respectively). These results suggest that p53 accumulation occurs more frequently in tumors with aggressive behavior and that p53 immunoreactivity may have a prognostic role in certain subsets of patients with ovarian carcinoma
Applicazione ai Tissue Microarray delle tecniche di immunoistochimica e di Ibridazione In Situ Fluorescente per la caratterizzazione immunofenotipica e citogenetica di linfoma a grandi cellule B diffuso
Full text linkObbiettivo
Lo scopo di questo lavoro è stato la costruzione di un Tissue Microarray (TMA) pilota per la
valutazione immunofenotipica e citogenetica di una casistica di linfoma a grandi cellule B diffuso
(DLBCL), tramite analisi immunoistochimiche e di Ibridazione In Situ Fluorescente (FISH).
Materiali e Metodi
Abbiamo costruito il TMA utilizzando le biopsie linfonodali di 12 pazienti affetti da linfoma a
grandi cellule B diffuso; ne abbiamo ottimizzato la costruzione per la lettura al microscopio a
fluorescenza distanziando in maniera differenziale i carotaggi dello stesso caso da quelli del
casi adiacenti mentre per mantenere la rappresentabilità tissutale abbiamo inserito cinque
carotaggi da 2 mm per campione. Al TMA abbiamo applicato cinque protocolli
immunoistochimici (CD10, BCL6, MUM1, GCET1 e FOXP1) e un protocollo FISH (cMYC).
Risultati
I dati immunoistochimici sono stati elaborati secondo gli algoritmi di Hans e Choi: secondo il
protocollo di Hans sono risultati 8 DLBCL con profilo immunofenotipico centro germinativo
simile (GCB) e 4 DLBCL con profilo attivato (ABC); in accordo con l'algoritmo di Choi 7 DLBCL
GCB e 5 DLBCL ABC. La conformità dei dati immunoistochimici ottenuti è stata valutata
confrontando i risultati con quelli delle indagini immunoistochimiche eseguite su sezione interna,
al momento della diagnosi. Abbiamo ottenuto in questo modo una concordanza del 100% con
l’algoritmo di Hans e una concordanza del 92% con l’algoritmo di Choi.
L’analisi di MYC non ha evidenziato la presenza di traslocazioni ma in tre casi è stato possibile
rilevare polisomie del cromosoma 8.
Conclusioni
Questo studio ci ha permesso di definire i criteri metodologici per la progettazione e la
costruzione di un TMA (con una concordanza del 100% rispetto ai dati ottenuti al momento
della diagnosi) che potesse essere letto agevolmente al microscopio a fluorescenza, fornendo
così una piattaforma di analisi ad alta resa per l'esecuzione di indagini immunoistochimiche e
citogenetiche FISH
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