1,720,975 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
INFRARED SPECTRA OF SMALL MOLECULAR PROBES IN LIQUID CRYSTALS
No full textAuthor Institution:Infrared absorption by the fundamentals of and in dilute solution in MBBA has been measured over the temperature range to . Band-shape analyses of the spectral profile show that the torque acting on the solute molecule varies rapidly through the nematic isotropic phase transition. These results demonstrate that small molecules can serve as molecular probes which are sensitive to solvent phase changes and suggest the application of this method to the study of membrane structure
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
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
From PbSe nanocrystals to PbSe/CdSe hetero-nanostructures : chemical synthesis and characterization of the physical properties
No full textDepuis les années 80, les nanocristaux (NCs) semi-conducteurs sont devenus très attractifs à cause d’énormes potentiels qu’ils représentent en termes d’applications technologiques. En effet, lorsque les dimensions d’un matériau deviennent inférieures ou comparables à la dimension caractéristique (rayon de Bohr) des porteurs de charges, les effets de confinement quantique conduisent à l’apparition de nouvelles propriétés physico-chimiques qui dépendent de la taille, la forme... Les NCs de chalcogénures de plomb possèdent des constantes diélectriques élevées et sont des matériaux de choix pour étudier les effets de confinement sur les propriétés des NCs dans le régime de confinement fort. Dans la première partie de cette thèse, les résultats obtenus sur la synthèse des NCs de PbSe et de PbSe/CdSe sont présentés. De taille très mono disperse et possédant une structure cristalline parfaite, ces NCs ont été synthétisés par voie colloïdale. Par la suite, les propriétés physico-chimiques de ces NCs ont été étudiées par diverses techniques de caractérisation (microscopies électroniques, diffraction des rayons X (XRD), diffraction électronique (SAED), spectroscopies Raman, absorption proche infrarouge et photoémission (UPS/XPS). Enfin, à l’aide des techniques de dépôts comme le Langmuir-Blodgett, des films minces de NCs de PbSe et de PbSe/CdSe ont été fabriqués. En utilisant un rayonnement synchrotron, la discontinuité des bandes dans les hétéro-nanostructures de PbSe/CdSe a été déterminée par XPS. Les résultats montrent un changement irréversible de la nature des NCs de PbSe/CdSe lors d’une irradiation prolongée de l’échantillon par un faisceau synchrotron.The tunability of electronic and optical properties of semiconductor nanocrystal (NC) is an important matter in nanotechnology because of their multiple potential applications in optoelectronics such as solar cells, nanotransistors, light emitters, biological markers…Core/shell QDs which are heterogeneous NCs have attracted increasing attention over the past decade, especially because of their enhanced photoluminescence properties and the possibility to create spatially separated excitons by means of a staggered core/shell band alignment. We studied lead chalcogenide NCs because of their unique physical properties which are very different from those of their corresponding bulk materials. Their high dielectric constant (ε∞=23 for PbSe) and the small effective masses of their electron and hole, create excitons with a relatively large effective Bohr radii. These properties lead to a strong confinement of the charge carriers and phonons., thus making them them promising building blocks for a wide number of applications. In the first part of this work, PbSe and PbSe/CdSe NCs with a narrow size distribution and high structural quality have been synthesized, using a colloidal route. Characterizations have been performed using several techniques (electron microscopy, X-ray diffraction (XRD), electron diffraction (SAED), photoemission (XPS/UPS), Raman and absorption spectroscopic measurements).By using deposition techniques such as Langmuir-Blodgett deposition, homogenous, compact thin films of PbSe and PbSe/CdSe NCs have been fabricated. UPS/XPS measurements performed with synchrotron radiations give the valence band offset between the core and the shell of these core/shell NCs
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