1,720,956 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
Development of Enhanced Algae Strains and Sustainable Cultivation Processes for Production of Algal Lipids for Biofuels and Bioproducts
No full textThe establishment of an algae industry is crucial for addressing global biofuel and bioproduct demand that meets the Sustainable Development Goals (SDG) worldwide. Photosynthetic microalgae are excellent sources for food, fiber, fuel, feed, and fertilizer, which are the 5Fs of the SDG. However, at present, algae-based materials are not cost-competitive or sufficiently sustainable. Improved productivity, lower cultivation cost, and reduced use of resources are required to transition from lab to industry, necessitating the development of superior strains that have high productivity and can tolerate environmental stress, such as temperature and salinity, so they can be cultivated at large scale outdoors using non-potable water. In this context, the present research aims at assessing a two-prong strategy for reducing the cultivation cost and enhancing the sustainability of algae cultivation: (1) using agricultural residues (sweet sorghum bagasse) as a source of renewable organic carbon and employing spent media recycling as a supplemental source of nitrogen and other nutrients; and (2) developing superior-performing algal strains that achieve high biomass and metabolite productivity, while possessing thermotolerance at high temperatures. The innovation of the study lies in the development of double-mutant algal strains using two genetic modification techniques, namely random mutagenesis and adaptive laboratory evolution, and the use of high-throughput multi-omics analysis (metabolomics and lipidomics) to elucidate the genetic modifications that occurred in the high-performing mutants. This way novel genetic targets can be identified to be used in the future to further improve strain performance. In this dissertation, four objectives were set and conducted to achieve the aforementioned goal. First, optimization of lipid productivity in Chlorella vulgaris under mixotrophic cultivation conditions using sweet sorghum bagasse hydrolysate and determination of alterations in the algal metabolism through lipidomics studies. In objective 1, C. vulgaris was successfully cultivated in SSB hydrolysate at optimized conditions achieving the highest lipid yield of 132 mg/L day, which proved that SSB hydrolysate can be used as an alternative carbon source for algae cultivation. In addition, LC-MS based lipidomics study revealed that when algal cells were cultured in SSB hydrolysate, MUFA, PUFA, and neutral lipids were enhanced, while a reduction in structural lipids was observed. In objective 2, a feasibility study was conducted to assess spent media recycling for algae cultivation in a custom-built 5-liter airlift photobioreactor and identify alterations in cell metabolism through metabolomic studies. The study demonstrated the feasibility of cultivating C. vulgaris in spent media, where cells exhibited increased carbohydrate, carotenoid, and C18:3 fatty acid content. Intracellular and extracellular metabolomics provided an insight into the algal cell and laid the groundwork for future improvements in algae tolerance to identified inhibitors. Objective 3 aimed at developing superior performing strains that can tolerate higher temperatures using UV mutagenesis and characterization of their biochemical make-up. Two UV mutants of Tetraselmis suecica were developed that outperformed the wild type and contained more lipids when grown at elevated temperatures. Objective 4 aimed at enhancing thermotolerant algal strains using EMS mutagenesis and adaptive laboratory evolution and determination of metabolic changes associated with such thermotolerance. This objective was accomplished by effectively generating high-lipid EMS mutants and adapting them to 33oC, which resulted in increased MUFA and PUFA production. Lipids produced by algae strains are viewed as promising feedstock for production of biofuels, like biodiesel and jet biofuel, and bioproducts, such as nutraceuticals, cosmetics, and pigments. Hence, this study aspires to develop algal strains tolerant to environmental stressors (sugars, recycled media, and heat) as a means of enhancing algal productivity, while improving the environmental and economic sustainability of future algal biorefineries
Sustainable Production of Bio-based Succinic Acid from Plant Biomass
Full text linkSuccinic acid is a compound used for manufacturing lacquers, resins, and other coating chemicals. It is also used in the food and beverage industry as a flavor additive. It is predominantly manufactured from petrochemicals, but it can also be produced more sustainably by fermentation of sugars from renewable feedstocks (biomass). Bio-based succinic acid has excellent potential for becoming a platform chemical (building block) for commodity and high-value chemicals.
In this study, we focused on the production of bio-based succinic acid from the fiber of sweet sorghum (SS), which has a high fermentable sugar content and can be cultivated in a variety of climates and locations around the world. To avoid competition with food feedstocks, we targeted the non-edible ‘bagasse’, which is the fiber part after extracting the juice. Initially, we studied various conditions of pretreating SS bagasse to remove most of the non-fermentable portions and expose the cellulose fibers containing the fermentable sugars (glucose). Concentrated (83%) phosphoric acid was utilized at mild temperatures of 50-80 °C for 30-60 minutes at various bagasse loadings (10-15%) using a partial factorial experimental design. After pretreatment, the biomass was subjected to enzymatic hydrolysis with commercial cellulase enzyme (Cellic® Ctec2) to identify the pretreatment conditions that lead to the highest glucose yield that is critical for the production of succinic acid via fermentation with the bacterium Actinobacillus succinogenes.
As the pretreatment temperature and duration increased, the bagasse color changed from light brown to dark brown-black, indicating decomposition, which ranged from 15% to 72%. The pretreatment results were fitted with an empirical model that identified 50 °C for 43 min at 13% solids loading as optimal pretreatment conditions that lead to the highest glucose release from sweet sorghum bagasse. Biomass pretreated at those conditions and subjected to separate enzymatic hydrolysis and fermentation with A. succinogenes yielded almost 18 g/L succinic acid, which represented 90% of the theoretical yield, a very promising performance that warranties further investigation of bio-based succinic acid production from sweet sorghum bagasse, as a more sustainable alternative to succinic acid produced from fossil sources, such as oil
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
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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