1,720,956 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
Theoretical investigation of 27Al chemical shifts dependence on water amount and temperature in zeolite MFI
No full textTitle: Theoretical investigation of 27 Al chemical shifts dependence on water amount and temperature in zeolite MFI Abstract: This bachelor thesis explores 27 Al NMR spectra in zeolite MFI and investigates the impact of several factors on the chemical shielding values, including water loading, temperature, and the relative positions of aluminum pairs. Various machine learning-based methods for calculating chemical shift are evaluated. Molecular dynamics simulations with neural network potentials are used to simulate experimental conditions. Neural network potentials offer a highly efficient means of calculating energy with a significant speed-up of approximately 1000 times faster than density functional theory, while maintaining a high level of accuracy. This study is the first to examine 27 Al NMR under operando conditions, with a focus on the experimentally relevant amount of water. Keywords: 27 Al NMR, machine learning, zeolites, MFI, operando conditions, neural network potential
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
Teoretické studium závislosti 27Al chemických posunů na množství vody v kanálech a na teplotě v zeolitu MFI
Get PDFTitle: Theoretical investigation of 27 Al chemical shifts dependence on water amount and temperature in zeolite MFI Abstract: This bachelor thesis explores 27 Al NMR spectra in zeolite MFI and investigates the impact of several factors on the chemical shielding values, including water loading, temperature, and the relative positions of aluminum pairs. Various machine learning-based methods for calculating chemical shift are evaluated. Molecular dynamics simulations with neural network potentials are used to simulate experimental conditions. Neural network potentials offer a highly efficient means of calculating energy with a significant speed-up of approximately 1000 times faster than density functional theory, while maintaining a high level of accuracy. This study is the first to examine 27 Al NMR under operando conditions, with a focus on the experimentally relevant amount of water. Keywords: 27 Al NMR, machine learning, zeolites, MFI, operando conditions, neural network potentialsNázev: Teoretické studium závislosti 27 Al chemických posunů na množství vody v kanálech a na teplotě v zeolitu MFI Abstrakt: Tato bakalářská práce zkoumá 27 Al NMR spektra v zeolitu MFI a zkoumá vliv několika faktorů na chemické stínění, včetně obsahu vody, teploty a relativních poloh hliníkových párů. Hodnoceny jsou různé metody výpočtu chemického posunu založené na strojovém učení. Molekulové dynamické simulace s využitím neuronových sítí jsou použity k simulaci experimentálních podmínek. Neuronové sítě nabízejí vysokou účinnost výpočtu energie s významným zrychlením, asi 1000krát rychlejší než teorie funkcionálu hustoty, při zachování vysoké úrovně přesnosti. Tato studie je první, která zkoumá 27 Al NMR za operando podmínek, s důrazem na experimentálně relevantní množství vody. Klíčová slova: 27 Al NMR, strojové učení, zeolity, MFI, operando podmínky, potenciály založené na neuronových sítíchKatedra fyzikální a makromol. chemieDepartment of Physical and Macromolecular ChemistryFaculty of SciencePřírodovědecká fakult
Modelování NMR vlastností zeolitů pomocí strojového učení a ab initio výpočtů
Get PDFThis study introduces a double machine learning approach, which combines neural net- work potentials (NNP) based molecular dynamics simulations with kernel ridge regres- sion (KRR) model to predict NMR parameters in aluminosilicate zeolites under experi- mentally relevant conditions. By capturing local atomic environments and interactions, this method accurately predicts 29 Si and 27 Al chemical shifts across a range of zeo- lite frameworks (MFI, RTH, CHA, etc.). This double machine learning approach is validated against both DFT calculations and experimental data, demonstrating high reliability and precision. While the application part of this work focuses primarily on interpreting experimental 29 Si-27 Al D-HMBC NMR spectra in RTH zeolite, the method- ology is expected to be broadly applicable to other spectroscopic analyses and materials. Furthermore, it is shown that most aluminium atoms in RTH occupy the T2 position, a finding not accessible through standard experimental techniques. These advancements enable efficient, large-scale simulations of complex zeolite systems, with significant im- plications for catalyst design and broader materials research. Keywords Zeolites, NMR, machine learning, aluminium distribution, DFTTato studie představuje metodu dvojitého strojového učení, která kombinuje simulace molekulární dynamiky založené na potenciálech neuronových sítí (NNP) s regresním modelem (KRR) pro predikci NMR parametrů v alumosilikátových zeolitech za ex- perimentálně relevantních podmínek. Zachycením lokálních atomárních prostředí a interakcí tato metoda přesně předpovídá chemické posuny 29 Si a 27 Al napříč různými ze- olitovými strukturami (MFI, RTH, CHA atd.). Tato metoda dvojitého strojového učení je ověřena jak vůči DFT výpočtům, tak experimentálním datům, což potvrzuje jeho vysokou spolehlivost a přesnost. Ačkoli se studie zaměřuje především na interpretaci experimentálních 29 Si-27 Al D-HMBC NMR spekter v zeolitech, očekává se, že použitá metodologie bude široce aplikovatelná i na jiné spektroskopické analýzy a materiály. Dále je ukázáno, že většina nejvíce atomů hliníku v RTH zaujímá pozici T2, což není přístupné standardními experimentálními technikami. Tyto pokroky umožňují efektivní a rozsáhlé simulace komplexních zeolitových systémů s významnými dopady na návrh katalyzátorů a širší materiálový výzkum. Klíčová slova Zeolity, NMR, strojové učení, distribuce hliníku, DFTDepartment of Physical and Macromolecular ChemistryKatedra fyzikální a makromol. chemieFaculty of SciencePřírodovědecká fakult
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
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