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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
Interactions between polyphenols and macromolecules facilitate the extraction of low viscosity banana juice
No full textBananas are an important staple food and cash crop throughout the African Great Lakes regionwhere they contribute highly to livelihood and food security. However, bananas are perishablefruits that require effective processing techniques to reduce post-harvest losses. Processingbananas into juice could be a better strategy for the mitigation of these losses and thus theimprovement of the banana value chain. Low viscosity banana juice has been produced in Eastand Central Africa for many years by mechanical blending and extraction, but the technology hasnot been industrialized due to some processing challenges. Occasional juice failures and cloudyappearance are among the problems related to banana juice production. Extraction of bananajuice using the mechanical method is limited to banana cultivars with high tannin content. Mostother banana cultivars do not produce juice by this method. The presence of tannins favorableto juice extraction seems to be related to the cultivar and ripening process.The challenges in the extraction of low viscosity banana juice have been associated with theability of the tannins to interact with proteins, but some studies suggest the involvement notonly of tannins and proteins but also of pectic polysaccharides. A better understanding of themechanisms behind banana juice extraction could be a solution to the ongoing challenges. Toaccomplish this, the overall aims of this thesis were to identify the physical and chemical factorsresponsible for juice release and the potential interactions between protein and phenoliccompounds. Phenolic and proteomic characterizations of juice-producing and cooking cultivarswere performed to investigate the potential link between the chemical composition of bananapulps and their ability to release juice. The nature of the interactions at different stages ofmechanical juice extraction was studied by Fourier Transform Infrared Spectroscopy (FTIR).Blending speed, extraction time and stage of ripeness were identified as significant factorsaffecting banana juice release with the optimum values of 2650 rpm, 162 s and stage 5,respectively. Chemical characterization revealed that juice-producing banana cultivars had ahigher content of total phenolic, tannins and gallocatechin monomers than non-juice producingbanana cultivars. There were no significant differences in protein content, molecular weightdistribution and amino acid composition among the cultivars. The observed band\u27s shifts of theFTIR spectra at the OH (3300.13-3270.94 cm-1), amide (1655.14-1641.89 cm-1) andpolysaccharide (995.65-875.08 cm-1) regions suggest interactions between phenolic compounds,proteins and pectins.The results in the present thesis show that the high content of phenolic compounds in bananasmay be the main factor for the ability of the banana pulps to release juice. In summary, theobserved changes in the functional groups of the pulp occurring during mechanical juiceextraction suggest that the mechanism behind banana juice extraction involves interactions ofphenolic compounds with both proteins and pectic polysaccharides. Further studies on thecharacterization of the banana pulp functional groups using Nuclear Magnetic Resonance areneeded to verify the mechanism behind banana juice release
Interactions between polyphenols and macromolecules facilitate the extraction of low viscosity banana juice
No full textBananas are an important staple food and cash crop throughout the African Great Lakes region where they contribute highly to livelihood and food security. However, bananas are perishable fruits that require effective processing techniques to reduce post-harvest losses. Processing bananas into juice could be a better strategy for the mitigation of these losses and thus the improvement of the banana value chain. Low viscosity banana juice has been produced in East and Central Africa for many years by mechanical blending and extraction, but the technology has not been industrialized due to some processing challenges. Occasional juice failures and cloudy appearance are among the problems related to banana juice production. Extraction of banana juice using the mechanical method is limited to banana cultivars with high tannin content. Most other banana cultivars do not produce juice by this method. The presence of tannins favorable to juice extraction seems to be related to the cultivar and ripening process. The challenges in the extraction of low viscosity banana juice have been associated with the ability of the tannins to interact with proteins, but some studies suggest the involvement not only of tannins and proteins but also of pectic polysaccharides. A better understanding of the mechanisms behind banana juice extraction could be a solution to the ongoing challenges. To accomplish this, the overall aims of this thesis were to identify the physical and chemical factors responsible for juice release and the potential interactions between protein and phenolic compounds. Phenolic and proteomic characterizations of juice-producing and cooking cultivars were performed to investigate the potential link between the chemical composition of banana pulps and their ability to release juice. The nature of the interactions at different stages of mechanical juice extraction was studied by Fourier Transform Infrared Spectroscopy (FTIR). Blending speed, extraction time and stage of ripeness were identified as significant factors affecting banana juice release with the optimum values of 2650 rpm, 162 s and stage 5, respectively. Chemical characterization revealed that juice-producing banana cultivars had a higher content of total phenolic, tannins and gallocatechin monomers than non-juice producing banana cultivars. There were no significant differences in protein content, molecular weight distribution and amino acid composition among the cultivars. The observed band's shifts of the FTIR spectra at the OH (3300.13-3270.94 cm-1), amide (1655.14-1641.89 cm-1) and polysaccharide (995.65-875.08 cm-1) regions suggest interactions between phenolic compounds, proteins and pectins. The results in the present thesis show that the high content of phenolic compounds in bananas may be the main factor for the ability of the banana pulps to release juice. In summary, the observed changes in the functional groups of the pulp occurring during mechanical juice extraction suggest that the mechanism behind banana juice extraction involves interactions of phenolic compounds with both proteins and pectic polysaccharides. Further studies on the characterization of the banana pulp functional groups using Nuclear Magnetic Resonance are needed to verify the mechanism behind banana juice release
The effect of local cassava processing methods on nutritional and sensory attributes of cassava flour: a case study of Newala district
No full textMSc. Dissertation in Food Science and TechnologyA study was carried out in Newala District to investigate the effect of different local
cassava processing methods on cyanogenic glucosides level, nutrient retention and colour
of cassava flour. Specifically the study was aimed at identifying different local cassava
processing methods, examining the effect of local processing methods on residual
cyanogenic glucosides in the cassava flours, examining the effect of local processing
methods on nutrient retention and color of cassava flour and study the cassava processing
and production constraints in the study area. In each study site, information was obtained
by focus group discussion, structured questionnaire from 40 households in each village.
Samples were collected for laboratory analysis. Results showed high total residual
cyanogen levels of about (790 ± 107 mg HCN equivalent/Kg dry weight) and (263 ± 71
mg HCN equivalent/Kg dry weight) in flour obtained from both small-size and large-size
niakopa respectively. Cyanohydrin levels were higher (39 ± 5 mg HCN equivalent/Kg dry
weight) in Chinyanya compared to levels of about (7 ± 2 mg HCN equivalent/Kg dry
weight) in the flour from large size makopa. Chinyanya showed to contain (75 g/1OOg,
starch, 1.3 g/1OOg protein, 32.8 g/1OOg vitamin C, 18.7 g/1OOg moisture and 13.22 pH,
Makopa showed to contain 80.0 g/1OOg starch, 2.72 g/1OOg protein, 24.52 g/1OOg vitamin
C, 12.5 g/1OOg moisture, at pH 10.28 where as fermented root showed to contain 65.2
g/1OOg starch, 0.75 g/1OOg protein, 15.4 g/1OOg vitamin C, 13.7 g/1OOg moisture, pH 5.25).
These findings confirmed that direct sun-drying of cassava roots is an ineffective method
for removal of cyanogenic glucosides as it yields products with relatively high residual
levels of cyanogenic glucosides while fermentation of cassava root is an effective method
in removal of total glucosides. Apart from colour preference, this study concluded that
although wet fermentation showed high nutrient loss, from the health point of view it is an effective way of reducing cynogenic glucosides level from cassava root, which are
dangerous for human health
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
The effect of local cassava processing methods on nutritional and sensory attributes of cassava flour: a case study of Newala district
No full textMSc. Dissertation in Food Science and TechnologyA study was carried out in Newala District to investigate the effect of different local
cassava processing methods on cyanogenic glucosides level, nutrient retention and colour
of cassava flour. Specifically the study was aimed at identifying different local cassava
processing methods, examining the effect of local processing methods on residual
cyanogenic glucosides in the cassava flours, examining the effect of local processing
methods on nutrient retention and color of cassava flour and study the cassava processing
and production constraints in the study area. In each study site, information was obtained
by focus group discussion, structured questionnaire from 40 households in each village.
Samples were collected for laboratory analysis. Results showed high total residual
cyanogen levels of about (790 ± 107 mg HCN equivalent/Kg dry weight) and (263 ± 71
mg HCN equivalent/Kg dry weight) in flour obtained from both small-size and large-size
niakopa respectively. Cyanohydrin levels were higher (39 ± 5 mg HCN equivalent/Kg dry
weight) in Chinyanya compared to levels of about (7 ± 2 mg HCN equivalent/Kg dry
weight) in the flour from large size makopa. Chinyanya showed to contain (75 g/1OOg,
starch, 1.3 g/1OOg protein, 32.8 g/1OOg vitamin C, 18.7 g/1OOg moisture and 13.22 pH,
Makopa showed to contain 80.0 g/1OOg starch, 2.72 g/1OOg protein, 24.52 g/1OOg vitamin
C, 12.5 g/1OOg moisture, at pH 10.28 where as fermented root showed to contain 65.2
g/1OOg starch, 0.75 g/1OOg protein, 15.4 g/1OOg vitamin C, 13.7 g/1OOg moisture, pH 5.25).
These findings confirmed that direct sun-drying of cassava roots is an ineffective method
for removal of cyanogenic glucosides as it yields products with relatively high residual
levels of cyanogenic glucosides while fermentation of cassava root is an effective method
in removal of total glucosides. Apart from colour preference, this study concluded that
although wet fermentation showed high nutrient loss, from the health point of view it is an effective way of reducing cynogenic glucosides level from cassava root, which are
dangerous for human health
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
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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