1,720,963 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
L-ergothioneine supplementation during culture improves quality of bovine in vitro-produced embryos
No full textThe aim of this study was to evaluate whether supplementation of bovine culture medium with the natural antioxidant L-ergothioneine (LE), improves in vitro blastocyst development and quality, assessed as resistance to cryopreservation, total cells number, cellular differentiation, and apoptosis index. Abattoir-derived oocytes were matured and fertilized in vitro according to standard procedure. Twenty hours after IVF, presumptive zygotes were cultured in synthetic oviduct fluid with 0, 0.05 mM, 0.1 mM, 0.5 mM, and 1 mM of LE (experiment 1) at 39 °C under humidified air with 5% CO2, 7% O2, and 88% N2. On the basis of the results of this dose-response trial, the range of concentrations to test was reduced in experiment 2, in which presumptive zygotes were cultured with 0, 0.05 mM, and 0.1 mM of LE. On Day 7, embryo yields were assessed, and the blastocysts (BL) were vitrified by Cryotop method in 16.5% ethylene glycol, 16.5% DMSO and 0.5 M sucrose. Finally, BL produced on Day 8 in the absence (control) and presence of 0.1 mM LE were used for transferase-mediated dUTP nick end labeling and differential staining to evaluate, respectively the apoptotic rate and the allocation of cells into inner cell mass (ICM) and trophectoderm lineages (experiment 3). Despite similar blastocyst yields, supplementation of culture medium with 0.1 mM LE improved the cryotolerance of in vitro-produced (IVP) embryos compared to the control group, as indicated by higher (P < 0.05) hatching rates recorded after 48-hour post-warming culture (48.5%, 50.0%, and 63.8%, respectively with 0, 0.05, and 0.1 mM LE). Interestingly, when embryos were cultured in the presence of 0.1 mM LE, the percentage of BL with the most physiological ICM:total cells ratio (20%-40%) increased (85.1 vs. 66.0%, P < 0.05), confirming a beneficial effect on embryo quality. Furthermore, 0.1 mM LE decreased (P < 0.01) both the average number (4.3 ± 0.2 vs. 9.1 ± 0.3) and the proportion (3.6 ± 0.3 vs. 8.1 ± 0.5) of apoptotic cells in BL compared to the control. In conclusion, the enrichment of bovine culture medium with 0.1 mM LE improves embryo quality, as indicated by the improved cryotolerance, the lower apoptotic rate, and the higher percentage of BL with the most physiological ICM:total cells ratio
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
Effect of L-ergothioneine supplementation during culture on in vitro embryo development in buffalo (Bubalus Bubalis)
No full textHYALURONIC ACID IMPROVES CRYOTOLERANCE OF BUFFALO (BUBALUS BUBALIS) IN VITRO-DERIVED EMBRYOS
No full textAlthough in vitro embryo production efficiency in buffalos has greatly improved over the years, the in vitro-produced embryos show lower viability and resistance to cryopreservation. Therefore, it is necessary to optimize the in vitro culture conditions to improve embryo quality. Hyaluronic acid, a glycosaminoglican present in oviducal and uterine fluids, has been shown to successfully support in vitro development of bovine embryos (Stojkovic et al. 2002 Reproduction 124, 141-153). The aim of this study was to evaluate the influence of high concentrations of hyaluronic acid (HA) during late in vitro culture on blastocyst development, as well as on their cryotolerance after cryotop vitrification in buffalos. In vitro matured and fertilized buffalo oocytes (n=1007) from slaughterhouse ovaries were cultured for 4 days in SOFaa supplemented by 8mgmL(-1) of BSA in a controlled gas atmosphere consisting of 5% CO(2), 7% O(2) and 88% N(2), in humidified air, at 38.5degreesC. On Day 4, cleavage rate was assessed (75.2%) and all of the cleaved elements were divided into 3 different late culture groups: 8mgmL(-1) of BSA (n=244; group A), 8mgmL(-1) of BSA supplemented by 6mgmL(-1) of HA (n=251; group B) and 1mgmL(-1) of BSA supplemented by 6mgmL(-1) of HA (n=262; group C). On Day 7 after IVF, embryo outcome was assessed and all of the embryos were vitrified by cryotop [De Rosa et al. 2007 Ital. J. Anim. Sci. 6 (Suppl 2), 747-750] and cultured for 24h. The resistance to cryopreservation was evaluated by assessing the survival rate on the basis of morphological criteria and the percentage of embryos reaching a more advanced developmental stage after 24h culture. Data were analysed by the chi-square test. No differences in blastocyst rate were recorded among groups (43.9, 44.3 and 40.0%, respectively in A, B and C groups). However, out of the total embryos, a higher percentage of Grade 1 hatched blastocysts (Robertson and Nelson 1998 Manual of the International Embryo Transfer Society 9, 103-16) was observed in group C (P<0.05) than in groups A and B (14.3, 18.8 and 25.5% in A, B and C groups, respectively). Although the supplementation with HA did not improve the survival rates following vitrification-warming (51.1, 59.4 and 58.4% in A, B and C groups, respectively), the percentage of vitrified-warmed embryos that resumed development and reached a more advanced developmental stage after culture increased (P<0.01) in group C (20.7, 27.7 and 37.6% in A, B and C groups, respectively). In conclusion, the addition of 6mgmL(-1) of HA, together with a limited protein source (i.e. 1mgmL(-1) of BSA), during late culture improved buffalo embryo quality, indicated by both the greater percentage of advanced-stage embryos and by the resumption of development after post-warming culture
Cytogenetic and genetic analyses of Wild Boar (Sus scrofa spp., 2n=36/37/38) reared in State-owned forestry company “Cerreta-Cognole”.
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