1,721,564 research outputs found
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
Food enrichment with omega-3 polyunsaturated fatty acids
No full textThe popularity of omega-3 long chain polyunsaturated fatty acids (PUFA) in terms of its health effects has persuaded consumers to buy foods enriched with these fatty acids. This trend has generated a growing interest in the production of these foods. However, susceptibility of omega-3 PUFA to oxidation and subsequent sensory issues in enriched foods have been long-lasting barriers for food producers. This chapter explains different aspects of lipid oxidation in enriched foods as influenced by the presence of prooxidants, processing and storage conditions, and packaging. Moreover, different delivery approaches, such as emulsification and encapsulation, for rendering stability to the enriched foods are discussed. Foods enriched with omega-3 PUFA are also summarized in different categories including dairy, dressings, spreads, bakery and meat products, and other foods such as ice cream and chocolate, and different aspects of their production, preservation, stability, and acceptance are overviewed
High fat (>50%) oil-in-water emulsions as omega-3 delivery systems
No full textHigh fat oil-in-water emulsions are used as delivery systems for fat-soluble bioactive compounds. Oil content in these systems varies substantially and can range from 50 to 80 wt%. High fat oil-in-water emulsions, due their higher volume fraction of dispersed phase, present special challenges in terms of physical and oxidative stability when compared to low fat oil-in-water emulsions. Particularly, the more pronounced packing of oil droplets in high fat oil-in-water emulsions affects its rheology and texture, as well as propagation of lipid oxidation, which will have an influence on their use as omega-3 delivery systems. This chapter discusses the main factors affecting physical and oxidative stability of high fat oil-in-water emulsions such oil content, emulsifier content and type, homogenization method, and addition of antioxidants. Moreover, the presence of metal ions in the ingredients used for production of the emulsion and/or in the food matrix and the pH of both the delivery emulsion and the enriched food system are also addressed as factors affecting the stability of high fat omega-3 delivery oil-in-water emulsions and final enriched food products
Introduction to delivery systems and stability issues
No full textFortifying food with omega-3 (n-3) long chain (LC) polyunsaturated fatty acids (PUFA) by using a delivery system can be an advantage, since a physical barrier is created covering the unsaturated lipids, which might protect the lipids from oxidative degradation. Omega-3 delivery systems are both in liquid (e.g., oil-in-water emulsions) and solid (e.g., nano-microcapsules/particles) forms. The latter relies on further processing of oil-in-water emulsions. In all cases, the production and stability of the delivery systems need to be optimized to avoid both physical destabilization and oxidative deterioration. Emulsion instability will result in decreased quality and will promote oxidative deterioration with nutritive loss of the healthy omega-3 LC PUFAs. This chapter introduces different physical and oxidative (chemical) stability issues related to emulsions
Lipid oxidation and traditional methods for evaluation
No full textLipid oxidation is one of the most important factors limiting the shelf life of oils rich in long-chain omega-3 fatty acids and delivery systems because it gives rise to the formation of volatile oxidation products, which will have a negative effect on sensory properties. This chapter summarizes the basic lipid oxidation reactions and also discusses a more complex, integrated reaction scheme including other reactions than formation of lipid hydroperoxides and aldehydes. Finally, the chapter provides an overview of different methods to analyze lipid oxidation products including simple spectrophotometric methods as well as newer advanced, instrumental methods such as NIR, FTIR, NMR, and GC-MS
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
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