1,720,961 research outputs found
Revisión bibliográfica: “Adaptaciones anatómicas de los delfines al medio marino”
Get PDFLa adaptación a la vida acuática ha orientado la evolución anatómica de los delfines. Es por ello que estos animales han debido adaptar su musculatura y esqueleto, hasta el punto incluso de perder estructuras, a una forma ahusada más hidrodinámica y desarrollar complejos sistemas de vascularización para poder mantener su temperatura corporal en el medio acuático. Por otro lado, el aparato respiratorio se ha adaptado también para mantener los grandes tiempos de inmersión y las altas presiones a las que son sometidos, e incluso han sido capaces de desarrollar un casi exclusivo sistema de ecolocalización altamente eficaz. Estas, entre muchas otras adaptaciones anatómicas, han conseguido que los delfines hayan podido sobrevivir en un medio tan hostil como el marino durante toda su existencia en el planeta.Adaptation to aquatic life has guided the anatomical evolution of dolphins. In such a way and broadly speaking, these animals have had to adapt their musculature and skeleton, to the point of even losing structures, to a more hydrodynamic tapered shape and had developed complex vascularization systems to be able to maintain their body temperature in the aquatic environment. On the other hand, the respiratory system has also been adapted to maintain long immersion times and the high pressures to which they are subjected to. Also, they have even been able to develop an almost exclusive, highly effective echolocation system. These, among many other adaptations, have made it possible for dolphins to survive in an environment as hostile as the marine environment throughout their existence on the planet.Veterinari
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
Influencia del tamaño de grupo y el periodo de puesta sobre la producción, el peso del huevo y la calidad de la cáscara en gallinas alojadas en jaulas
Get PDFEl huevo de gallina (Gallus gallus) es un alimento considerado básico, con
un consumo extendido en todo el mundo, por su contenido nutricional y por no
haber restricciones religiosas para su consumo. La población española valora a la hora de comprar huevos factores como la frescura, el tamaño y precio, seguidos del sistema de producción. Existe una tendencia, principalmente en los países europeos, encaminada a un aumento de la cría de gallinas en sistemas libres de jaulas, aunque la gran mayoría de los huevos que se producen en el
mundo lo son en sistemas de jaulas, por su eficacia productiva y rentabilidad
económica.
Partiendo de la hipótesis de que las gallinas alojadas en jaulas son
capaces de alcanzar altos niveles de producción, sin que estos se vean alterados negativamente por el sistema de alojamiento y el manejo, se realizó este estudio cuyo objetivo fue evaluar la producción, la tasa de mortalidad, el consumo de
alimento, el peso y la calidad externa de la cáscara de los huevos producidos por gallinas alojadas en tres tamaños de grupo (20, 26 y 60 gallinas), los tres grupos
con la misma densidad de población.
Se estudiaron 22 lotes de gallinas Hy-Line (2.849.869 gallinas) alojadas en 22 naves con baterías de jaulas enriquecidas que cumplían con los requisitos de la Directiva 99/74/EC. El periodo de recogida de datos abarcó desde junio de
2018 hasta noviembre de 2020. Las gallinas se alojaron en baterías en tres tipos
de jaulas enriquecidas, con una capacidad de 20 (S20), 26 (S26) y 60 gallinas (S60). Cada gallina disponía de más de 750 cm2 de superficie en los tres tipos de jaula. El ciclo de puesta se dividió en tres periodos: Inicial de las 19 a las 26
semanas de vida, Medio de las 27 a las 52 semanas de vida y Final de las 53 a
las 74 semanas de vida. Las variables que se estudiaron fueron el número de
huevos totales (HT), el número de huevos sucios (SUC), el número de huevos rotos (ROT), el número de huevos fisurados (FIS), el número de huevos
clasificados S, M, L y XL, así como el consumo de alimento (CONSUM),
expresado en gramos por ave/día) y la mortalidad (MORT).
El análisis del tamaño de grupo no mostró diferencias significativas en los
datos obtenidos para el porcentaje de puesta, mortalidad, huevos de categoría L y porcentaje de huevos sucios. El porcentaje de huevos XL fue mayor en las gallinas alojadas en el grupo de menor tamaño (S20), mientras que los huevos M fueron más numerosos en el grupo S26. Para las variables correspondientes a la integridad de la cáscara, el porcentaje de huevos rotos fue menor en S20, y
para los huevos que presentaban fisuras el grupo S60 fue el que presentó una
mayor incidencia. El consumo de alimento fue mayor en el grupo de menor
número de aves, S20.
La fase productiva influyó sobre todas las variables estudiadas. El
porcentaje de puesta fue significativamente mayor durante el período Medio, mientras que la mortalidad fue mayor en el periodo Final. Referente al peso del
huevo los datos obtenidos reflejaron un mayor porcentaje de huevos XL en la
fase Final, periodo en el que se contabilizaron un mayor número de huevos rotos
y fisurados. El consumo de pienso por gallina fue menor en el periodo Inicial. En
el grupo de 20 gallinas se registraron los mejores datos para el peso de huevo XL y la menor cantidad de huevos rotos y fisurados, por lo que se propone como
el tamaño de grupo recomendado para optimizar la rentabilidad de las jaulas.Chicken eggs (Gallus gallus) are considered a staple food, widely
consumed throughout the world, due to their nutritional content and the fact that there are no religious restrictions on their consumption. When buying eggs, the
Spanish population values factors such as freshness, size and price, followed by the production system. There is a trend, mainly in European countries, towards an increase in the rearing of hens in cage-free systems, although the vast majority
of eggs produced in the world are produced in cage systems, due to their productive efficiency and economic profitability.
Based on the hypothesis that hens housed in cages are capable of
achieving high levels of production, without these being negatively altered by the
housing system and management, this study was conducted to evaluate the
production, mortality rate, feed consumption, weight and external shell quality of
eggs produced by hens housed in three group sizes (20, 26 and 60 hens), all
three groups at the same stocking density.
Twenty-two flocks of Hy-Line hens (2,849,869 hens) housed in 22
enriched cage battery houses complying with the requirements of Directive 99/74/EC were studied. The data collection period covered from June 2018 to
November 2020. The hens were housed in batteries in three types of enriched
cages, with a capacity of 20 (S20), 26 (S26) and 60 hens (S60). Each hen had
more than 750 cm2 of floor space in all three cage types. The laying cycle was
divided into three periods: Initial from 19 to 26 weeks of age, Middle from 27 to
52 weeks of age and Final from 53 to 74 weeks of age. The variables studied
were the number of total eggs (HT), the number of dirty eggs (SUC), the number
of broken eggs (ROT), the number of cracked eggs (FIS), the number of eggs classified S, M, L and XL, as well as feed consumption (CONSUM), expressed in
grams per bird/day) and mortality (MORT).
.
Cluster size analysis showed no significant differences in the data
obtained for laying percentage, mortality, L grade eggs and percentage of dirty eggs. The percentage of XL eggs was higher in hens housed in the smallest group size (S20), while M eggs were more numerous in the S26 group. For the
shell integrity variables, the percentage of broken eggs was lower in S20, and for
cracked eggs the S60 group had the highest incidence. Feed consumption was highest in the group with the lowest number of hens, S20.
The production phase influenced all the variables studied. Laying
percentage was significantly higher during the Middle period, while mortality was higher in the Final period. Egg weight data showed a higher percentage of XL
eggs in the Final period, when a higher number of broken and cracked eggs were
counted. Feed consumption per hen was lower in the Initial period. The group of
20 hens had the best data for XL egg weight and the lowest number of cracked and broken eggs and is therefore proposed as the recommended group size to
optimise cage profitability.VeterinariaCiencias de la Vida y del Medio Natura
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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