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Effect of seminal plasma removal, washing solutions, and centrifugation regimes on boer goat semen cryopreservation
No full textImproved Cryopreservation of Boer Goat Semen
Get PDFRecently, interest in the cryopreservation of spermatozoa as a potential source of valuable genes has escalated to improve reproductive efficiency and productivity in livestock such as goats. The objectives of this study were to improve the quality of semen cryopreservation media, technique of cryopreservation, and to analyse the effects of various factors on goat sperm survival after freezing and thawing. To conduct this research, eleven Boer goats were used and semen was collected twice a week using an artificial vagina. For initial evaluation, the semen samples were assessed for volume, colour, consistency, mass activity, sperm concentration, sperm morphology, and percentage of motile spermatozoa. The qualified semen samples between one and two mL volume with a concentration of greater than 2.5 X 10 9 sperm/mL having >75% progressively motile sperm and >85% of the sperm with normal morphology were selected for cryopreservation. The qualified ejaculates were then diluted with the semen extenders and packed in 0.25 mL. French straws. After equilibration, cooling and freezing procedures were carried out in a cooling chamber and liquid nitrogen. Two days later, the semen was thawed at 37˚C for 30 sec and evaluated for the semen qualitative parameters such as motility, acrosome integrity, membrane integrity, live and normal spermatozoa percentages. Data were analyzed using ANOVA, followed by Tukey’s post hoc test to determine significant differences in all the parameters between groups using the SPSS software system. The effects of four different sugars on semen quality were analyzed for the improvement of semen cryopreservation media in Boer goats. This study was conducted to analyze firstly the effect of two monosaccharides and two disaccharides in Boer goat semen cryopreservation, secondly, to investigate the combination effects of trehalose and other sugars, and finally to find out the most effective concentration of trehalose combination for Boer semen cryopreservation. The combination of 69.38 mM glucose and 198.24 mM trehalose conferred the practical and beneficial effects in cryopreservation of Boer goat spermatozoa. The effects of four cryoprotectants, different concentrations of glycerol and three glycerolization procedures with two cooling times for Boer goat semen cryopreservation were evaluated through analysis of motility parameters. The use of glycerol cryoprotectant at the concentration of 7% conferred the best cryoprotective effect for Boer goat semen cryopreservation. In addition, the use of three-step dilution method (mC) and three hour cooling time improved semen quality after cryopreservation. The effects of four amino acids (alanine, glycine, cysteine and glutamine) at concentrations of 20, 40, and 60 mM on semen quality were examined in Boer goat semen cryopreservation. The effect of different concentrations of cysteine (0, 5, 9.5, 15.5, 20 mM) on cryopreservation semen was subsequently evaluated to find out the optimum concentration to improve semen quality after cryopreservation. Cysteine at the concentration of 5 mM provided the most effective protection against cryodamage by improving post-thawed semen quality during cryopreservation process in Boer goat semen. Three experiments were conducted to determine the effects of seminal plasma removal using two different extenders, the effects of three different washing solutions and the effects of different centrifugation regimes on the characteristics of Boer goat semen before freezing and after thawing. This study showed that the removal of seminal plasma by centrifugation at 3000 x g for 3 min with Tris citric acid glucose washing solution in Boer goat semen cryopreservation protocol could be used to improve sperm survival in Boer goat semen cryopreservation. However, these results are based on in vitro evaluations, further fertility trials are requires as ultimate test of improved cryopreservation
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
Dispelling 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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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