1,720,995 research outputs found
Uso de secuestrantes para disminuir la toxicidad de micotoxinas en alimentos para acuacultura.
Get PDFLa presencia de micotoxinas en alimentos para animales terrestres y acuáticos puede llegar a reducir significativamente el crecimiento, consumo de alimento, sobrevivencia e incrementar la tasa de conversión alimenticia así como causar afeccciones en el sistema inmune, por lo que pueden ser responsables de pérdidas económicas considerables. Para prevenir la contaminación de los ingredientes con micotoxinas durante su cultivo, cosecha y almacenamiento se han utilizado un sin número de procedimientos como buenas prácticas agrícolas, selección de semillas resistentes al ataque de hongos y a la formación de micotoxinas, uso de compuestos químicos durante el almacenamiento, remoción de micotoxinas por procesos físicos, etc., no obstante, en algunas ocasiones no se logra impedir la generación de estas toxinas. La inclusión de remediadores como: secuestrantes, biotransformadores y compuestos protectores son otras alternativas que permiten reducir al máximo la presencia de estas sustancias en los alimentos terminados o disminuir los estragos cuando los animales consumen alimentos contaminados con micotoxinas. En este trabajo se presenta una revisión general del uso de estos productos en alimentos para animales terrestres y acuáticos, incluyendo estudios de su efectividad in vivo así como consideraciones importantes al momento de incluirse en alimentos terminados
Apparent dry matter, protein and amino acid digestibility of six rendered animal products in litopenaeus vannamei juveniles.
Get PDFLa digestibilidad aparente de materia seca, proteína cruda y aminoácidos individuales de 6 subproductos de rastro fue determinada in vivo al incluir los subproductos al 30% en dietas prueba para alimentar juveniles de camarón blanco del Pacifico (peso inicial 5g), el 70% restante siendo la mezcla de referencia, constituida de una dieta comercial molida suplementada con 1% de alginato de sodio como aglutinante, y 1% de óxido de cromo como marcador inerte. El estudio se llevó a cabo con dos harinas de subproductos de pollo grado mascota (72.3 y 68.6% PC = proteína cruda en base seca), dos harinas de pluma (85.5 y 86.7% PC), una harina de sangre de pollo (94.5%PC) y una harina de subproductos de cerdo (58.5% PC), procedentes de diferentes procesadoras de EUA. La digestibilidad de materia seca fue significativamente mayor en las harinas de pollo o de cerdo (69-73%) que en harinas de sangre o pluma (57-62%), pero fue menor en todos los productos que en la dieta de referencia (78%), formulada a base de harinas de pescado, pasta de soya y trigo. La misma tendencia se observó para digestibilidad de proteína cruda (ref 84% > pollo o cerdo 75-80% > pluma o sangre 57-62%) y para la suma de aminoácidos (ref 88% > pollo o cerdo 74-80% > pluma o sangre 65-67%). La digestibilidad de aminoácidos individuales mostró variaciones importantes entre productos y entre aminoácidos: la cistina fue el aminoácido menos digestible, con una diferencia de -7% en sangre, -10% en pluma, -17% en pollo y -37% en cerdo con respecto a la digestibilidad de proteina cruda. Los aminoácidos de mayor digestibilidad fueron histidina y glicina en general. Arginina, metionina y lisina, así como la suma de aminoácidos totales o esenciales, mostraron digestibilidades cercanas a la de proteína cruda. Las concentraciones de aminoácidos digestibles, tomados individualmente, fueron mayores en harinas de sangre y de pollo que en la dieta de referencia; pero en harinas de pluma, los niveles de histidina, metionina y lisina digestibles fueron muy bajos, así como en harina de cerdo los niveles de cistina, metionina, isoleucina y leucina digestibles
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
Recent advances in the application of stable isotopes as nutritional tools in aquaculture
Get PDFFrom an ecological point of view, aquaculture systems consist of simple food webs having a limited number of nutritional sources. These characteristics facilitate the application of stable isotope ratios of carbon and nitrogen (δ13C and δ15N) to assess the flow of dietary components. Due to rapid and measurable bioaccumulation of the heavier stable isotopes, such isotopic shifts can be tracked at different times and at each trophic step to provide an indicator of what dietary components are being incorporated into animal tissue and how fast. The present manuscript presents results from recent, controlled nutritional experiments designed to quantify the relative contribution of dietary carbon and nitrogen supplied by different dietary items. Stable isotopes ratios were measured in a range of food sources and experimental animals. In a first experiment, juvenile shrimp Litopenaeus vannamei were reared on co-feeding regimes having different proportions of live biomass of the green macroalgae Ulva clathrata and inert feed in order to identify nutritional contributions to tissue growth using dual stable isotope analysis. In another trial, nitrogen stable isotopes were measured to explore the relative dietary nitrogen contributions from fish meal and pea meal (Pisum sativum) to the growth of white shrimp postlarvae fed low protein diets having different proportions of both ingredients. In a third, multidisciplinary experiment, Senegalese sole (Solea senegalensis) larvae were used as a model to evaluate the effect of different larval feeding regimes on (1) trypsinogen gene expression (ssetryp1), (2) trypsin and chymotrypsin activities and (3) changes in stable isotope composition to estimate the assimilation of dietary carbon from the larval diets
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
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