1,720,956 research outputs found

    Sewage sludge as an alternative resource: Optimization of media for citric acid production

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    Sewage is the largest contributor of organic pollution to water resources as well as to surrounding environments all over the world. In Malaysia, its contribution is top listed (64.4%), followed by animal husbandry wastes (32.6%), agro-based (1.7%) and industrial effluent (1.3%) in terms of the BOD load (Alam et al. 2009). Approximately 4.2 million cubic meters of sewage sludge (pure organic waste without mixing with the industrial waste) is produced annually by Indah Water Konsortium (IWK), a national sewerage company in Malaysia and the total cost of managing is estimated at RM 1 billion (Kadir and Velayutham, 1999). The country has to adopt a practical, economic, and acceptable approach in managing and disposing sewage sludge. Present practice is either to co-dispose it with solid waste at landfill sites or direct disposal in shallow trenches (Zain et al., 2001). However, the safe and environmental-friendly disposal of this huge quantity of sludge is the main concern of IWK. Sludge can be a very good source of carbon, nitrogen, phosphorus and other nutrients for many microbial processes. Therefore, the production of citric acid using sewage sludge as the sole media would be an alternative to overcome sludge disposal problem as well as to fulfill the demand of this organic acid globall

    Process optimization in citric acid production using sewage sludge as fermentation media

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    A research has been conducted on liquid state bioconversion for the production of citric acid using Sewage Treatment Plant (STP) sludge as main substrate and added with sucrose as co-substrate. Three parameters were examined as to determine the best process optimization conducted in two liter (2L) bioreactor. Two level factorial designs with three parameters are applied for the fermentation. It was carried out using local isolates Aspergillus niger strain O103A at room temperature (30-32oC), agitation is set at three different values which are 100, 200 and 300rpm. Initial pH for fermentation is set at 5 and it was further adjusted to three levels which are 2, 3, and 4 on the second day of the fermentation. Another parameter is aeration where 1, 1.5 and 2 vvm were introduced. The fermentation was carried out for five days. The maximum yield of citric acid obtained throughout the fermentation is 23.68 g/L, which is due to low pH, low agitation and high aeration values

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

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    “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

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    We 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

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    We 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

    Author Index

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    koamabayili/VECTRON-author-checklist: VECTRON author checklist

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    We 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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