1,720,991 research outputs found
Utilización de leguminosas forrajeras como abonos verdes para la producción de cultivos forrajeros y leche en ganaderías doble propósito en el trópico seco
Full text linkLos sistemas ganaderos de doble propósito en el trópico son afectados durante la época seca con reducción en la producción de leche, debido a la disminución en la cantidad y calidad de los forrajes. El impacto de la sequía se puede disminuir mediante el uso de cultivos forrajeros como suplementos, pero requieren aplicación de N, lo cual no es económicamente viable. Una alternativa es usar leguminosas forrajeras como abonos verdes en rotación con cultivos forrajeros para que suplan N. Sin embargo, su adopción en sistemas ganaderos ha sido muy baja, posiblemente debido a que los productores no ven beneficios directos de su uso en producción de leche. En este estudio se evaluó y cuantificó como el uso de leguminosas forrajeras como abonos verdes en sistemas lecheros tropicales contribuye en forma directa a la producción de leche cuando se suplementan vacas con leguminosas henificadas, y en forma indirecta cuando la leguminosa no cosechada para henificar se usa como abono en rotación con cultivos forrajeros para ensilar. Se determinó el aporte de N de leguminosas usadas como abono verde en producción de forraje de maíz. El aporte equivalente de N varió entre 35 y 151 kg ha-1, siendo el mayor aporte con la leguminosas Canavalia ensiformis y el menor con V. unguiculata. También se evaluaron cuatro leguminosas y dos niveles de N con dos manejos (M1: siembra del cultivo forrajero 4 meses después de incorporado el abono y M2: siembra del cultivo 1 mes después de incorporado el abono). C. brasiliensis y L. purpureus son una opción para ser usadas como abono verde en sistemas ganaderos en trópico seco. Los manejos de abonos verdes no afectaron el rendimiento de maíz, pero sí podrían tener efectos ambientales negativos. Adicionalmente, se encontró que hasta con un 50% de remoción de biomasa de una leguminosa cultivada como abono verde no se afectó en forma significativa (p 0,05) el rendimiento (11.283 kg MS ha-1) del cultivo forrajero en comparación con el control de no remoción (11.382 kg MS ha-1). Cuando se suplemento a vacas con heno de leguminosa producido a partir de la biomasa removida del abono verde se logró un aumento de 17% en producción de leche con un nivel de suplementación de 1,5% del PV/día. También se generaron recomendaciones específicas de fertilización nitrogenada, en función de expectativas de producción usando el sistema experto NuMaSS. Se establecieron tres experimentos con diferentes niveles de N y la incorporación de leguminosas como abono verde en maíz. Las recomendaciones generadas con NuMaSS indican que las leguminosas aportan N suficiente para el maíz (36 - 79 kg N ha-1). En general, el estudio indica que con la integración de leguminosas forrajeras como abonos verdes y como alimento para el ganado en sistemas ganaderos doble propósito en el trópico seco, sería posible reducir costos de producción de cultivos forrajeros y aumentar la producción de leche en época seca, lo cual a su vez puede contribuir a la adopción de abonos por ganaderos, repercutiendo en mayor rentabilidad y competitividad de los sistemas doble propósito.Abstract. The dual-purpose cattle systems in the tropics are affected during the dry season with reduction in milk production due to the decrease in the quantity and quality of forage. The impact of drought can be reduced through the use of forage crops as supplements, but require application of N, which is not economically viable. An alternative is to use legumes as green manure in rotation with forage crops that replace N. However, its adoption in livestock systems has been very low, possibly because producers do not see direct benefits of its use in milk production. This study assessed and quantified as the use of legumes as green manures in tropical dairy systems contributes directly to milk production when cows are supplemented with legume hay, and indirectly supplemented when the legume is not harvested for hay used as manure in rotation with forage crops for silage. N supply of legumes used as green manure in forage maize production was determined. The equivalent contribution of N varied between 35 and 151 kg ha-1, with the largest contribution to the legume Canavalia ensiformis and V. unguiculata lower with. Four pulses and two levels of N were also assessed with two managements (M1: forage crop planting four months after the fertilizer and M2: crop planting built one month after the payment). C. brasiliensis and L. purpureus are an option to be used as green manure in farming systems in dry tropics. The handling of green manure did not affect corn yield, but may have negative environmental effects. Additionally, it was found that up to 50% removal of biomass from a legume grown as green manure was not affected significantly (p 0.05) yield (11.283 kg DM ha-1) compared to forage crop removal not control (11.382 kg DM ha-1). When I was supplemented cows legume hay produced from biomass removed from the green manure an increase of 17% in milk production with supplementation level of 1.5% LW/day was achieved. Specific nitrogen fertilization recommendations were also generated depending on production expectations NuMaSS using the expert system. And the incorporation of legumes as green manure on corn. Three experiments with different levels of N were established. The recommendations generated by NuMaSS indicate that legumes provide sufficient N for corn (36-79 kg N ha-1). Overall, the study indicates that the integration of legumes as green manure and as cattle feed in dual purpose cattle systems in the dry tropics, could reduce production costs of fodder crops and increase milk production in the dry season, which in turn can contribute to the adoption of fertilizers by farmers, affecting greater profitability and competitiveness of dual purpose systems.Doctorad
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Evaluación de adaptación y estabilidad fenotípica de genotipos de raigrás (Lolium spp.) en tres localidades de la zona productora de leche del trópico alto de Nariño
Full text linkEn el trópico alto de Nariño, se encuentra una de las cuatro cuencas lecheras de Colombia, en la cual predomina el pasto Kikuyo (Cenchrus clandestinum), forraje naturalizado, susceptible a heladas, plagas y enfermedades que afectan su productividad. Con el fin de mejorar la oferta forrajera, se evaluó la adaptación y estabilidad fenotípica de 10 genotipos de raigrás (Lolium spp.) en los municipios de Pasto, Cumbal y Sapuyes. Los experimentos se establecieron bajo el diseño de bloques completos al azar, con cuatro repeticiones. Se realizó un análisis de varianza combinado bajo un modelo factorial, donde el factor A fue la localidad (3), el B la época de corte (lluviosa y seca), el C la edad de corte (25, 30, 35 y 40 días) y el factor D los genotipos (10). También, se realizó un análisis de adaptabilidad y estabilidad para rendimientos de forraje verde (RFV) y materia seca (RMS) por medio de los modelos de Eberhart y Russell y AMMI. Los genotipos Aubade, Bestfor Plus, Boxer y Tetralite II presentaron los mayores rendimientos de forraje verde (7,51 – 8,31 t/ha/corte) y de materia seca (1,29 – 1,37 t/ha/corte). Mediante el modelo Eberhart y Russell, por RFV, estos genotipos fueron clasificados con mejor respuesta en ambientes favorables y predecibles y por RMS también fueron predecibles, pero Aubade y Bestfor Plus se clasificaron con buena respuesta en todos los ambientes y Boxer y Tetralite II, con mejor respuesta solo en ambientes favorables. El modelo AMMI permitió identificar a Pasto como el ambiente más favorable y a los genotipos Boxer y Tetralite II como los de mejor comportamiento en este ambiente.//Abstract: In the high tropic of Nariño, is one of the four milk basins of Colombia, in which predominates the Kikuyo grass (Cenchrus clandestinus), a naturalized forage, susceptible to frosts, pests and diseases that affect their productivity. In order, to improve the forage supply, the adaptation and phenotypic stability of 10 genotypes of ryegrass (Lolium spp.) In the municipalities of Pasto, Cumbal and Sapuyes was evaluated. The experiments were established under the design of complete blocks at random, with four repetitions. A combined analysis of variance was carried out under a factorial model, where factor A was the location (3), B the cutting season (rainy and dry), C the cut age (25, 30, 35 and 40 days) and factor D genotypes (10). Also, an adaptability and stability analysis was carried out for green forage (RFV) and dry matter (RMS) yields through the Eberhart and Russell and AMMI models. The genotypes Aubade, Bestfor Plus, Boxer and Tetralite II had the highest green forage yields (7.51 - 8.31 t / ha / cut) and dry matter (1.29 - 1.37 t / ha / cut). Using the Eberhart and Russell model, by RFV, these genotypes were classified with better response in favorable and predictable environments and by RMS they were also predictable, but Aubade and Bestfor Plus were classified with good response in all environments and Boxer and Tetralite II, with better response only in favorable environments. The AMMI model allowed to identify Pasto as the most favorable environment and the Boxer and Tetralite II genotypes as those with the best behavior in this environment.Maestrí
Variations on the Author
Full text link“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
Full text linkWe 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
Full text linkWe 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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