1,721,027 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
Spontaneous and iatrogenic ovarian hyperstimulation syndrome in the absence of FSHR mutations: a case report of two unexpected cases
Full text linkBackground: Ovarian hyperstimulation syndrome (OHSS) is a complication of controlled ovarian hyperstimulation (COH). It is a potentially life-threatening condition that usually occurs either after human chorionic gonadotropins (hCG) administration in susceptible patients or as a result of an implanting pregnancy, regardless of whether it was achieved by natural conception or infertility treatments. Despite many years of clinical experience regarding the adoption of preventive measures and the identification of patients at high risk, the pathophysiology of OHSS is poorly understood and no reliable predictive risk factors have been identified. Cases presentation: We report about two unexpected cases of OHSS following infertility treatments, occurring after freeze-all strategy with embryo cryopreservation approaches. The first case developed spontaneous OHSS (sOHSS), despite efforts to prevent its manifestation by a segmentation approach, including frozen embryo replacement cycle. The second case developed a late form of iatrogenic OHSS (iOHSS), even though the absence of any risk factors. No mutations in the follicle-stimulating hormone (FSH) receptor (FSHR)-encoding gene were detected, suggesting that the high levels of hCG due to the twin implanting pregnancies could be the only triggering factor of OHSS outbreak. Conclusion: Freeze-all strategy with embryo cryopreservation cannot entirely prevent the development of OHSS, which may occur in its spontaneous form independently from the FSHR genotype. Although OHSS remains a rare event, all infertile patients requiring ovulation induction or controlled ovarian stimulation (COS) may be at potential risk of OHSS, either in the presence or in the absence of risk factors. We suggest closely monitoring cases of pregnancy following infertility treatments in order to provide early diagnosis and adopt the conservative management
Maternal anaphylaxis and fetal brain damage after intrapartum chemoprophylaxis.
No full textWe report a case of maternal anaphylaxis following intrapartum chemoprophylaxis. The term fetus developed severe brain damage as a consequence of intrapartum asphyxia. The lesions resulted from maternal hypotension following anaphylaxis. We discuss the feto-maternal risks and the controversial treatment of such a condition. The increasing number of penicillin-treated parturients will result in further cases of maternal anaphylaxis than previously found
Pulsatile fluctuations of plasma-gonadotropin-releasing hormone and corticotropin-releasing factor levels in healthy pregnant women.
No full textSeveral data emphasize the neuroendocrine aspects of human placenta. Classical hypophyseotropic neurohormones are produced and secreted by the human placenta. Indeed, in contrast with non pregnant subjects, gonadotropin-releasing hormone (GnRH) and corticotropin-releasing factor (CRF) are measurable in maternal plasma during pregnancy. The aim of the present study was to investigate the characteristics of the secretory pattern of maternal plasma GnRH and CRF levels. A total of 25 healthy pregnant women participated in the present cross-sectional study. Plasma levels of the two neurohormones were measured according to three different time-intervals: 1) every five minutes for eight hours (n = 4), 2) every ten minutes for four hours (n = 15), 3) every four hours for 24 hours (n = 7). Following an acidic extraction plasma GnRH and CRF levels were measured by specific radioimmunoassay. Using two different algorithms (Detect and Cluster) a pulsatile pattern for both plasma GnRH and CRF levels was observed. Specific pulse frequency, amplitude, and duration were found. In the groups of women studied with a longer sampling interval, pulse frequency of GnRH or CRF levels did not differ between first and third trimester of gestation. However, amplitude of CRF pulses were significantly higher at term than at early stages of pregnancy (p < 0.01), while GnRH pulse amplitude was highest in women at first trimester of gestation. Evaluating the degree of concordance in all subjects, GnRH pulses significantly correlated with CRF pulses at 30 min. lag (p < 0.01). No significant circadian changes were found for any circulating neurohormone measured.(ABSTRACT TRUNCATED AT 250 WORDS
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