1,720,963 research outputs found
Linking nursery practices and reforestations
No full textThe choice of nursery practices is important to the production of high-quality seedlings and to increase the survival rates of reforestation plantations in the dry tropics. However, adequate practices need to be established for native species for which propagation information is scarce. This study suggests that light management in nurseries is a key cultivation practice for future planting success, because of the morpho-physiological changes that plants usually undergo in different light conditions. We examined variations in the morphology, photosynthesis efficiency and growth of Pithecellobium dulce plants produced under four levels of light in nursery conditions (20%, 40%, 60%, and 100% of photosynthetically active radiation [PAR]). We also assessed survival after planting out according to the light conditions under which the plants were grown. Morpho-physiological variables were examined in three-month-old plants. A plantation was established in the field using the nursery-grown plants, and their survival was recorded monthly for 17 months. In the nursery, the light levels had significant effects on morphology, photosynthesis efficiency and growth. The 60% PAR level was favourable to optimum results for most of the variables, whereas the least successful results were found in plants grown at 20% PAR. Seedling survival in the field differed significantly according to the nursery light level, increasing with greater light intensity in the nursery during seedling production. 100% survival was observed in seedlings produced under 100% PAR, whereas the lowest survival rate (53%) was found in seedlings grown under 20% PAR. Light management thus shows potential as a cultivation practice by affecting the quality of P. dulce seedlings, which is improved in the nursery at 60% PAR. However, better survival after planting out is obtained with plants produced under full sun. These results should help to improve nursery management and establishment in the field of P. dulce in projects to restore degraded lands in the dry tropics
Calidad de planta de Enterolobium cyclocarpum y Swietenia humilis.
No full textCon base en el contexto de que la poda aérea y la fertilización en vivero son prácticas culturales que mejoran la calidad de planta siempre y cuando la intensidad de poda y el régimen de fertilización sean apropiados; se examinaron los efectos de tres intensidades de poda aérea (0%, 25% y 50%) y de dos regímenes de fertilización (tradicional y exponencial) en plantas de Swietenia humilis mediante la evaluación de diversos indicadores morfológicos y fisiológicos de calidad, y de un ensayo de prueba de calidad. No existió una sinergia entre ambas prácticas; no obstante, de manera independiente cada factor influyó en los indicadores evaluados. La poda aérea tanto al 25% como al 50% no mejoró la calidad de planta de S. humilis. En cambio, el suministro de nutrimentos en forma exponencial si tuvo un efecto favorable. Los resultados aportados por el ensayo de prueba de calidad hicieron patente que las características adquiridas por efecto de la fertilización exponencial permiten a las plantas desempeñarse satisfactoriamente cuando la baja disponibilidad de nutrimentos es un factor limitante. _______________ ABSTRACT: Based on the context that top pruning and fertilization in the nursery are cultural practices that improve seedling quality as long as the intensity of pruning and fertilization regime are appropriate, the effects of three top pruning intensities (0%, 25% and 50%) and two fertilizer regimes (traditional and exponential) in Swietenia humilis seedlings were studied throughout the evaluation of various morphological and physiological indicators of quality, and a quality test trial. There was no synergy between the two practices; yet, each factor influenced independently on the indicators evaluated. The top pruning at 25% and 50 % did not improve the seedling quality of S. humilis. In contrast, the exponential supply of nutrients had a favorable effect. The results provided by the quality test trial showed that characteristics acquired by the exponential fertilization effect allow seedlings to perform satisfactorily when low nutrient availability is a limiting factor.Tesis (Maestría en Ciencias, especialista Forestal).- Colegio de Postgraduados, 2013.Consejo Nacional de Ciencia y Tecnología (CONACYT)
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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