1,720,987 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Utilizing bio-based structures for tunable water transport in membranes and coatings
No full textWaterproof, breathable materials (WBMs) serve various purposes, ranging from water filtration to food packaging, with a familiar application being rain jackets. The primary function of rain jackets is to keep a user dry by blocking liquid water while allowing the transmission of water vapour. WBMs achieve this with two key components: an external hydrophobic coating and an internal membrane. However, coatings often contain perfluorinated compounds (PFCs) that are hazardous to human health, and the membranes have a water vapour transmission rate (WVTR) too low to match the body’s sweat rate. This work introduces PFC-free, superhydrophobic coatings that are both biodegradable and bio-sourced. Water-repellent coatings were prepared from commercially unavailable plant waxes. A plant survey was conducted, and the bulk extraction of waxes from conifer trees yielded a mixture of hydrophobic and hydrophilic compounds. Therefore, a purification process was tested, and it was determined that, although the wax extract outperformed commercial products, removing noncrystallizing wax components did not significantly enhance the coating's performance. It was shown that, using less coating material than commercial coatings, high-performing petroleum-free coatings could be made and applied onto textiles of various polarities without a costly purification step. Additionally, to enhance the WVTR of existing membranes, we developed intracellularly hydrogelated isolated guard cells (iGCs), intended for future incorporation into microporous membranes. Through this work, guard cells (GCs) were successfully isolated with their cell walls intact from the leaves of Vicia faba, allowing further in-depth analyses into the cell wall composition of GCs. Additionally, we intracellularly infused the hydrogel polymer PEG-DA into the iGCs through photoactivated crosslinking. By incorporating a hydrogel intracellularly within iGCs, this work aided in the preservation of GCs with minimal compositional loss, offering potential future insights into their composition and plant actuation mechanisms. In conclusion, this work overcomes the human health hazards of existing coatings through the development of plant-based alternatives. Furthermore, it tackles the WVTR challenges of existing membranes through the successful isolation and modification of GCs, with the hope of future developments resulting in responsively breathable membranes.Applied Science, Faculty ofChemical and Biological Engineering, Department ofGraduat
Cellulose nanocrystals : from extraction to biomedical application
No full textWith societal, industrial, and clinical progress continuously reaching greater heights, the crucial need for enhanced materials with versatile properties is ever increasing to help this growth. As such, polymer nanocomposites (PNCs) have been heavily researched, becoming redefined as their own class of materials, focusing on fundamental structure/property relationships, manufacturing techniques, and commercial applications, due to their remarkable properties and application versatility. Through countless nanoparticle and polymer matrix variations, PNCs can be finely-tuned to exhibit a multitude of unique characteristics. Utilizing this concept, the research laid out in the combined chapters of this dissertation sought to produce various PNCs embedded with cellulose nanocrystals/nanofibrils (CNCs/CNFs) and magnetic nanoparticles (MNPs) to obtain uniquely tunable properties to further progress the biomaterials field for biomedical applications. Initially, CNCs were extracted from the otherwise useless agricultural waste product of spent coffee grounds through phosphoric acid hydrolysis, and analyzed using multiple physical and chemical characterization techniques. In particular, a few crucial properties determined were aspect ratio of 12 ± 3, crystallinity of 74.2%, surface charge density of 48.4 ± 6.2 mmol/kg cellulose, and the ability to successfully reinforce PNCs, comparing well to other literature data and common commercial CNCs. Following extraction, CNCs/CNFs, as well as MNPs, were incorporated into various polymer matrices, including poly(ethylene glycol) diacrylate, sodium alginate, gelatin, and polyurethane, among others. Through solution casting and 3D bioprinting fabrication methods, as well as composition manipulation, CNCs/CNFs were able to reach ideal percolating networks within the PNCs for maximum mechanical reinforcement with minimal hindrance of the polymer matrix’s natural properties. The various PNC hydrogel scaffolds successfully demonstrated tunability of their nanostructural, mechanical, hydration, and biodegradation properties, utilizing the benefits of manipulated composition, crosslinking density, and nanofiller orientation to increase versatility for tissue engineering constructs. Additionally, MNP incorporation was shown to successfully produce inductive heating responses to promote topographical shape memory effects, while invoking minute thermal dissipation into surrounding environments to reduce thermal shock to seeded biological components. The success of this work makes strides to overcome a few crucial disadvantages of current PNC biomaterial hydrogels, specifically their inability to regenerate biomimetic native tissues during wound healing.Applied Science, Faculty ofChemical and Biological Engineering, Department ofGraduat
Synthesis and valorization of uniform lignin nanoparticles by subcritical water/solvent systems
No full textAs the second most abundant naturally occurring polymer on the planet, lignin is extracted during the pulping and bleaching of many pulp and paper products. Despite millions of tons of lignin being extracted every year, the vast majority of this amorphous, amphiphilic polymer is burned for energy. Lignin’s heterogenous and variable nature make it a challenging material to work with, but production of lignin nanoparticles (LNPs) can valorize lignin by improving its uniformity, miscibility, and functionalization potential. However, existing methods for synthesis of these nanoparticles generally require time-consuming, multi-step processes with specialized laboratory-scale equipment, or require high volumes of toxic organic solvents to produce relatively low volumes of LNPs. Herein, we outline and assess a novel process for synthesis of uniform LNPs, using subcritical water (scH₂O) as a solvent and ambient water as an antisolvent for kraft lignin. This process, assisted by volumes of easily recyclable organic solvent several times lower than previously reported in the literature, synthesizes chemically and morphologically homogenous nanoparticles in high yield. A range of reactor conditions and solvent/water ratios were considered for their efficacy at producing LNPs, and the effect of a kraft lignin pre-fractionation step was assessed for its ability to improve nanoparticle yield. The effects on nanoparticle chemical structure, thermal stability, suspension stability, morphology, and yield were considered for a range of solvent/water ratios. To further highlight the potential for valorization of lignin, we produced sulfonated lignin nanoparticles (NanoSL) via a traditional solvent-antisolvent (SAS) precipitation process and produced thermally and structurally stable polyvinyl alcohol (PVOH)/NanoSL films. These films were assessed for their potential application as proton exchange membranes (PEMs) for redox flow battery (RFB) systems. These membranes demonstrated electrochemical properties comparable to commercially available membranes, and improved structural properties compared with other bio-based membranes, including unmodified sulfonated lignin-based membranes.Applied Science, Faculty ofChemical and Biological Engineering, Department ofGraduat
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