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Efecto de la temperatura en la calidad espermática de la lagartija Sceloporus megalepidurus
Get PDFAdemás de diferentes reacciones químicas y fisiológicas, ejercer un óptimo control de la temperatura es importante para la correcta síntesis, diferenciación y maduración espermática. En organismos ectotermos, este factor térmico depende mayormente del entorno en el que el organismo se encuentre y desarrolle, mismo que se ha visto afectado a lo largo de los años, mostrando un incremento considerable, teniendo como consecuencia aspectos que van desde cambios en la distribución hasta la extinción de dichas especies. Estos resultantes han permitido inferir que la reproducción es uno de los aspectos afectados por el aumento de la temperatura, conllevando a defectos en los procesos que intervienen en la calidad espermática de los organismos, sin embargo, la investigación en estos caracteres ha sido mayormente enfocada en mamíferos, por lo que resulta importante conocer qué es lo que ocurre con los reptiles y si es considerable enfocar este punto en la mira para la comprensión y esfuerzo por la conservación de estas especies. El presente estudio se enfoca en evaluar el efecto de la temperatura en la calidad espermática en una población de la especie Sceloporus megalepidurus en los alrededores de la Laguna de Tecocomulco, Hidalgo. Los individuos fueron colectados durante el mes de octubre de 2020, donde se examinaron un total de 22 animales (15 machos y 7 hembras), de los cuales posteriormente se utilizaron sólo machos para la investigación correspondiente. Se determinó la temperatura preferida (Tsel) de la especie, se evaluó la anatomía de testículos y epidídimos, además del análisis de los parámetros espermáticos. Las observaciones en campo y gradiente de S. megalepidurus manifiestan un aspecto de termoconformidad en la especie (Ts = 33.64 ± 3.20; Tc machos = 32.19 ± 1.37; Tc Hembras = 31.77 ± 1.33). Así mismo, los individuos sometidos a temperatura preferida promedio y su límite superior (33.64 °C y 36 °C respectivamente) presentaron efectos negativos en parámetros anatómicos y espermáticos, destacando una disminución en el tamaño gonadal (no significativo) así como en la viabilidad, concentración (no significativo) e integridad de ADN espermáticos, además de la retención en el porcentaje de gota citoplásmica (GC), comparados con los tratamientos a temperaturas inferiores (28 °C y 30 °C).In addition to different chemical and physiological reactions, exercising optimal temperature control is important for correct sperm synthesis, differentiation and maturation. In ectothermic organisms, this thermal factor depends mainly on the environment in which the organism is found and develops, which has been affected over the years, showing a considerable increase, resulting in aspects ranging from changes in distribution until the extinction of these species. These results have allowed to infer that reproduction is one of the aspects affected by the increase in temperature, leading to defects in the processes that intervene in the sperm quality of organisms, however, research on these characters has been mostly focused on mammals, so it is important to know what is happening with reptiles and whether it is important to focus on this point in order to understand and endeavor to conserve these species. The present study focuses on evaluating the effect of temperature on sperm quality in a population of the species Sceloporus megalepidurus in the surroundings of Laguna de Tecocomulco, Hidalgo. The individuals were collected during the month of October 2020, where a total of 22 animals (15 males and 7 females) were examined, of which only males were subsequently used for the corresponding investigation. The preferred temperature (Tsel) of the species was determined, the anatomy of testes and epididymis was evaluated, in addition to the analysis of sperm parameters. Field and gradient observations of S. megalepidurus show an aspect of thermoconformity in the species (Ts = 33.64 ± 3.20; Tc males = 32.19 ± 1.37; Tc females = 31.77 ± 1.33). Likewise, the individuals subjected to the preferred temperature and its upper limit (33.6 ° C and 36 ° C respectively) presented negative effects on anatomical and sperm parameters, highlighting a decrease in gonadal size (not significant) as well as in viability, concentration (not significant) and integrity of sperm DNA, in addition to the retention in the percentage of cytoplasmic droplet (GC), compared with the treatments at lower temperatures (28 ° C and 30 ° C)
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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