1,720,962 research outputs found
Nitrogen Losses and Enrichment of Soil and Sawdust Coverings during Composting of Poultry Manure
No full textAims: Composting poultry manure is an effective way of enhancing its nutrient content and reduce nutrient losses. There is the need to reduce gaseous nutrient losses during composting through the use of covering materials. Assess the level of chemical enrichment of soil and sawdust used as covering materials; and identify the most suitable medium that can best perform as a covering material during composting of poultry manure.
Materials and Methods: Experiments were set up to examine the changes in the chemical properties of soil and sawdust used as covering material for composted poultry manure. Five treatments – no covering, layers of 2.8 kg soil, 5.6 kg soil, 0.9 kg sawdust, and black polythene sheet on 5.28 kg broiler and layer manure heaps with four replications were arranged in a completely randomized design. Samples were taken from the manure piles and the soil and sawdust covering materials for chemical analysis at 3, 6 and 9 weeks after composting.
Results: The pH, N, P, K, Na and Ca, in both soil covers increased as time elapsed, whereas the Mg and C/N ratios of the soil coverings decreased with time. With regards to the broiler manure, however, the pH and the nutrient content of the two levels of soils used as cover increased at all the stages of composting. Composting of both poultry manures resulted in the improvement of the chemical properties of both sawdust and soil coverings. The enrichment ratio of N was greater in the 5.6 kg soil than the 2.8 kg soil covering. Additionally, the 5.6 kg soil covering was highly efficient (P = .05) in reducing N losses by 57 and 83.85% from the broiler and layer piles, respectively. In general, the 5.6 kg soil was the most effective covering material
Analysis of Hydraulic Resistance of Soil Surface Seals in Relation to Sediment Particle Size
No full textSurface sealing, and their role in runoff and erosion, especially, in agricultural fields have been recognized as major set-backs to irrigation operations. Though the process is restricted to only the topmost soil layer of some few millimetres in depth, surface sealing can substantially impede the infiltration of water into the soil. However, information on this process is much less documented. The aim of this study was to investigate the possible relationships between seal type and hydraulic resistance. The paper presents a simple theoretical approach which allows the estimation of changes in hydraulic resistance at the soil surface as a function of time following the formation of surface seals formed from different sediment particles at different concentrations in suspension. A laboratory column studies was designed to investigate the effects of water quality on infiltration rate. Clear water, and muddy water comprising sand, silt and clay at different concentrations of 10, 20, 30 and 40 g in 400 cm3 of water were used as the test fluids
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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