1,721,109 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
Atomistic Modeling and Computational Study of Reactive Systems and Biological Applications
Get PDFThis dissertation covers several atomistic modeling techniques and applications in various fields that were classified into two major categories: quantum chemistry and reactive molecular modeling for materials designs (Chapters 2-4) and protein simulation for biological systems (Chapter 5-7). Despite the differences in modeling techniques and application areas with the two categories, all studies employed atomistic simulations to characterize the structures, thermodynamics, and kinetics of the systems of interest, helped understand the fundamental mechanics and driving forces of materials/proteins behaviors that cannot be solely described by experiments, and predicted optimal processing conditions or molecular structures following the process-structure-property relationship.The fundamentals of density functional theory (DFT) and molecular dynamics (MD) simulations are introduced in Chapter 1. DFT is a computational modeling method that is based on quantum mechanics and investigate the electronics structure of many-body systems, which allows for the understanding of atomic bonding and reaction mechanisms. However, its limitations in time scale and length scale made it unsuitable for applications where dynamics is important and reactions happen with larger molecules or systems. Therefore, we utilized reactive MD by parametrizing empirical reactive force fields, Tersoff and ReaxFF, to study the structure changes, reaction mechanisms, and thermodynamic and kinetic properties of surface modification, aqueous reaction, and photo-initiated polymerization. The force fields were fitted against DFT-calculated structures, atomic charges, and energetics, and detailed DFT methods, parametrization algorithms and process, and ReaxFF formalism were described in Chapter 1.
Chapter 2 focuses on applying the above techniques to develop a Tersoff force field for atomic layer etching where incident chlorine adsorbed on germanium (001) surface and modified the surface, followed by energetic Argon bombardment. Reactive MD simulations were then carried out using the developed Tersoff force field to study the correlations between the chlorination energy and penetration depth/ surface coverage, and the Ar bombardment energy and etched product species. Threshold bombardment energy and completion bombardment energy were also determined. This was a collaborative project with Lam Research, and our computational study gave insights with experimental parameters optimization. Chapter 3 focuses on the development of a ReaxFF force field for validating the reaction mechanism of a novel CO2 absorbent – phosphoenol pyruvate (PEP). MD simulations with this force field described the process where PEP in water transferred bicarbonate, which was converted from CO2, into carboxyphosphate and enolate, and investigated the correlation between the phosphorous’ reactivity and partial charge. Chapter 4 focuses on the development of a ReaxFF force field for photo-initiated acrylate free-radical polymerization. This is a collaborative project with the volumetric additive manufacturing (VAM) team in Lawrence Livermore National Lab, as photopolymer resin design is a crucial part in the VAM process. MD simulations with this force field compared the structures and dynamic properties of three acrylates with different numbers of vinyl groups, sizes and shapes, and depicted their polymerization processes. This study not only provided a reactive force field suitable for acrylate polymerization, but also enabled future benchmark studies for resin materials selection.
Chapter 5-7 are the works that studied the interactions between the glycosylated recombinant ACE2 and the receptor-binding-domain (RBD) of the SARS-CoV-2 spike protein. In Chapter 5 we developed fully glycosylated computational models of ACE2-Fc fusion proteins that were therapeutically designed to neutralize SARS-CoV-2 spike protein, and this study was further extended to investigate the relationship between glycosylation and the binding of SARS-CoV-2 spike to ACE2 in Chapter 6. Two different glycovariants of ACE2 were built, pulling simulation were conducted for the binding strength between SARS-CoV-2 spike and ACE2, and hydrogen bond interactions analysis and spatial analysis of glycan interactions were used to study the binding regimes under the influence of glycans. These computational analyses offer insights for future designs of glycoproteins as therapeutic baits. The final Chapter 7 focuses on a collaborative work where we performed structural stability comparisons of various spike truncations that are experimentally synthesized in Chinese hamster ovary cells for therapeutic and diagnostic applications
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
Simulation von ORMOCER®-Materialien mit klassischen und reaktiven Kraftfeldmethoden
No full text[no abstract
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
- …
