1,722,301 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
LOCALIZATION OF ADENOSINE RECEPTORS IN RAT TESTICULAR CELLS
No full textThe localization of adenosine receptors in rat testicular cells was investigated by evaluating the binding of cyclohexyladenosine (CHA) to somatic and germ cells and by assessing the effect of purine nucleosides on the function of testicular cells. Most of the specific binding of CHA in the testicular homogenate was found in the seminiferous tubule fraction, with little specific binding present in the interstitial compartment. Specific binding was also detected in a total-cell suspension prepared by dispersion of the seminiferous tubules. However, the specific activity of the binding did not increase when such a suspension was fractionated to produce germ cells at different stages of spermatogenesis. Adenosine receptors were present in the crude particulate fraction prepared from testes of rats from 10 to 90 days of age. While the affinity of these receptors did not vary as the testis matured, the number of binding sites per testis increased markedly up to 60 days after birth. Conversely, when binding activity was expressed per mg of testicular protein, no major changes in the specific activity of the binding were detected in testes up to 90 days of age. Sertoli cell-enriched cultures possessed a large number of binding sites, with a receptor density of 722 +/- 147 fmoles bound/mg protein (mean +/- SE; n = 5) and an affinity constant (Kd) of 1-2 nM. Among the characteristics of this binding site were kinetics constants and specificity similar to those measured in total particulate fractions of the testis and in the brain. Specific binding of CHA was not detected in cultures of testicular peritubular cells.(ABSTRACT TRUNCATED AT 250 WORDS
FSH regulates maternal mRNA translation in the oocyte and promotes developmental competence
No full textThe development of the ovarian follicle is under the control of the gonadotropins FSH and LH. FSH promotes granulosa cell growth and prepares the follicle to respond to LH, whereas the LH surge is the major signal for oocyte meiotic resumption and ovulation. However, an increased secretion in FSH accompanies the LH surge prior to ovulation in most mammalian species. The exact function of this FSH surge is unclear even though it is thought to be important for oocyte maturation and developmental competence. In rodents, FSH and the growth factor EGF have been shown to increase the developmental competence of cumulus oocyte complexes matured in vitro. Improvement in fertilization and pregnancy rates has been demonstrated in IVF patients stimulated with FSH/hCG compared to hCG alone. The signaling pathways and mechanisms by which FSH improves oocyte quality are unknown. Here we have tested the hypothesis that FSH improves oocyte quality by regulating the translation of maternal mRNAs in mouse oocytes. Experiments were conducted in cumulus oocyte complexes (CEOs) collected from ovaries of 21-24 days old PMSG-primed mice, and cultured in groups of 30-50. All the experiments were repeated 3-6 times. Data were analyzed by t-test, OneWay ANOVA or TwoWay ANOVA. P values <0.05 were considered statistically significant. Dual luciferase translation reporters were co-injected in oocytes still enclosed in the cumulus cells. The translation of prototypic luciferase reporters (Tpx2 and interleukin7 – Il7 3’UTRs) was significantly increased when CEOs were cultured in the presence of FSH. Consistent with the increased translation, the IL7 secretion was significantly higher in the culture supernatant of CEOs cultured with FSH compared to control. The FSH-dependent increase in translation was preceded by a transient phosphorylation of AKT in the oocyte, measured by western blot. Knockdown of the expression of the EGF receptor (Egfr) in the granulosa/cumulus cells using a genetic approach (EgfrΔ/loxP:Cyp19cre) prevented the oocyte AKT activation by FSH. These results indicate that the FSH signal transduction requires EGFR for its action. To further investigate the role of PI3K/AKT in the regulation of oocyte translation by FSH and its effect on developmental competence we used a genetic model where Pten (phosphatase and tensin homologue), which negatively regulates PI3K, is specifically ablated in oocytes. AKT was constitutively activated in PtenloxP/loxP:Zp3cre oocytes, independently of the culture treatment. In absence of any hormone, the constitutive AKT activation was sufficient to induce an increase in the translation of the luciferase reporters compared to controls. The fertilization rate was significantly increased in PtenloxP/loxP:Zp3cre oocytes in the absence of hormone treatment. These data strongly suggest that FSH promotes oocyte developmental competence by regulating translation in the oocyte, a regulation that requires an intact EGFR signaling in cumulus cells. These findings provide a molecular rationale for the use of FSH to improve egg quality during assisted reproductive technologies. Supported by: FP7-PEOPLE-2013-IOF GA 624874 MateRNA and NICHD-NIH NCTRI P50HD05576
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
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
Cloud tracking using satellite data for predicting the probability of heavy rainfall events in the Mediterranean area
No full textThe use of cloud tracking techniques and storm identification procedures is proposed in this paper with the aim of predicting the evolution of cloud entities associated with the highest rainfall probability within a given meteorological scenario. Suitable algorithms for this kind of analysis are based on the processing of digital images in the thermal infrared (IR) band from geostationary satellites: a selection of such algorithms is described in some detail together with a few real case applications. Three heavy rainfall events have been selected for this purpose with reference to the extreme meteorological situation observed during Fall 1992 and 1993 over the Mediterranean area. A window from 30 to 60 degrees N and from 20 degrees W to 30 degrees E has been identified for the analysis of data from the radiometer on board the ESA Meteosat platform. In conclusion, the suitability of cloud tracking techniques for predicting the probability of heavy rainfall events is discussed provided that the former are associated with proper modeling of small scale rainfall distribution
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