1,720,994 research outputs found
Delayed application of N-rich substrate affects GHG emissions during composting
No full textDissertação de Mestrado em Engenharia AgronómicaA significant amount of nitrogen (N) is lost during composting and this loss reduces the fertilizing value of the final product. Greenhouse gas emissions (GHG) – mainly methane (CH4) and nitrous oxide (N2O) – also occur during composting. High temperatures (> 45°C) increase ammonia volatilisation. The addition of an N-rich substrate after the thermophilic phase (late addition) is therefore proposed as a way of reducing nitrogen losses and GHG emissions from composting thereby improving the agronomic value of the final product. Vermicomposting – composting by earthworms – has also been suggested for reducing N losses from composting. However, the effect of these practices on the GHG emissions is unclear. The objective of this thesis was, therefore, to investigate the effect of delayed addition of N-rich substrate on greenhouse gas emissions during composting and link this effect to the different composting method. The results showed that the treatments with early addition increased CO2 production (P = 0.03), irrespective of the composting method. Apart of the mixing ratios of the substrate, vermicomposting increased the CO2 emissions by 22 - 47% compared with traditional composting (P < 0.01). Vermicomposting also increased N2O emissions (P = 0.01) by 160 – 230%, but decreased CH4 emissions (P = 0.01) from 97-253%. The timing of substrate addition on GHG emission showed the same pattern regardless the composting methods. Delayed addition increased N2O emissions, but reduced CH4 production. With vermicomposting, the NO3- concentrations increased from 90%-140% and the NH4+ concentrations decreased by 23 – 44% except in the 3rd treatment where it increased 98%. The pH dropped ( 0,5 – 3%) in the presence of earthworms. In conclusion, the timing of addition of N-rich substrate influences the total GHG emissions and chemical properties of compost and hence further studies are suggested to understand the mechanisms
Delayed application of N-rich substrate affects GHG emissions during composting
Full text linkDissertação de Mestrado em Engenharia AgronómicaA significant amount of nitrogen (N) is lost during composting and this loss reduces the fertilizing value of the final product. Greenhouse gas emissions (GHG) – mainly methane (CH4) and nitrous oxide (N2O) – also occur during composting. High temperatures (> 45°C) increase ammonia volatilisation. The addition of an N-rich substrate after the thermophilic phase (late addition) is therefore proposed as a way of reducing nitrogen losses and GHG emissions from composting thereby improving the agronomic value of the final product. Vermicomposting – composting by earthworms – has also been suggested for reducing N losses from composting. However, the effect of these practices on the GHG emissions is unclear. The objective of this thesis was, therefore, to investigate the effect of delayed addition of N-rich substrate on greenhouse gas emissions during composting and link this effect to the different composting method. The results showed that the treatments with early addition increased CO2 production (P = 0.03), irrespective of the composting method. Apart of the mixing ratios of the substrate, vermicomposting increased the CO2 emissions by 22 - 47% compared with traditional composting (P < 0.01). Vermicomposting also increased N2O emissions (P = 0.01) by 160 – 230%, but decreased CH4 emissions (P = 0.01) from 97-253%. The timing of substrate addition on GHG emission showed the same pattern regardless the composting methods. Delayed addition increased N2O emissions, but reduced CH4 production. With vermicomposting, the NO3- concentrations increased from 90%-140% and the NH4+ concentrations decreased by 23 – 44% except in the 3rd treatment where it increased 98%. The pH dropped ( 0,5 – 3%) in the presence of earthworms. In conclusion, the timing of addition of N-rich substrate influences the total GHG emissions and chemical properties of compost and hence further studies are suggested to understand the mechanisms
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
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
Climate-smart agricultural practices – Definitions, challenges and opportunities in Ethiopia
Full text linkDispelling 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
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