1,720,970 research outputs found
Fraccionamiento y caracterización de proteínas del plasma seminal de carnero (Ovis aries) por cromatografía de afinidad a fibronectina colectado en estación reproductiva.
No full textTesis presentada para optar al título de Médico Veterinario.En el plasma seminal (PS) de carnero hay un grupo de proteínas que tienen la característica de presentar dominio a fibronectina tipo II (Fn-II). Estas proteínas se unen a la membrana plasmática del espermatozoide al momento de la eyaculación ejerciendo una acción estabilizante del plasmalema. El objetivo de este estudio fue implementar un procedimiento de fraccionamiento y caracterización de las proteínas del PS de carnero para la obtención de la fracción proteica con dominio Fn-II. Se utilizó semen de 5 carneros colectado por vagina artificial. El PS fue precipitado con etanol frío y centrifugado. El pellet resuspendido en buffer fosfvato salino (PBS) fue transferido a una columna de Gelatina-Sepharosa y lavado sucesivamente con PBS. Las proteínas adheridas (fracción proteica con dominio Fn-II) fueron eluidas con una solución 5M de urea en PBS. La cuantificación proteica se realizó a través del método de Bradford y para la determinación de la masa molecular las fracciones fueron corridas en electroforesis usando geles de poliacrilamida (SDS-PAGE). La cromatografía muestra 2 fracciones proteicas, A y B, la primera corresponde al lavado con PBS y la segunda corresponde a la elusión usando solución de urea. Se recobró alrededor de un 85,4% del total de proteínas del PS ingresado a la columna, correspondiendo un 72,7% a la fracción A y un 12,7% para la fracción B. La fracción B reveló la presencia de 2 bandas proteicas, la primera con masa molecular entre 7 y 17 KDa y la segunda banda con masa molecular entre 17 y 25 KDa. Las proteínas obtenidas podrían ser utilizadas en estudios en biotecnología de semen en rumiantesFacultad de Ciencias VeterinariasDepartamento de Ciencias PecuariasChillá
Luteotrophic effect of OIF/NGF in llamas
Get PDFAn Ovulation-Inducing Factor (OIF) isolated from llama seminal plasma has recently been identified as Nerve Growth Factor (NGF). This protein not only has a potent ovulatory but also a luteotrophic effect in llamas after intramuscular or intrauterine infusion. The objective of the present review is to summarize the results of the effect of OIF/NGF on Corpus Luteum (CL) development in llamas. The results of a series of experiments demonstrate that the luteotrophic effect of OIF/NGF is mediated by a change in the secretion pattern of the LH surge. The intramuscular administration of OIF/NGF increases progesterone secretion regardless of the size of the preovulatory follicle at the time of treatment. The repeated administration of OIF/NGF during the periovulatory period (preovulatory, ovulatory, early postovulatory) increases CL size, vascularization and progesterone production. The effect of OIF/NGF varies with the route of administration (intramuscular, intravenous and intrauterine). It was concluded that OIF-NGF elicits a preovulatory LH surge followed by ovulation and development of a functional CL, regardless of the route of administration. However, with the intrauterine treatment, a physiological dose of OIF/NGF was required to elicit pituitary and ovarian responses
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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