1,721,061 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
New functionalities of bottlebrush copolymers in concentrated mineral suspensions
No full textLa thèse porte sur une nouvelle classe de polymères à architecture en brosse, synthétisés à l'échelle industrielle et utilisés comme additifs dans les suspensions colloïdales pour le couchage du papier. Le polymère en brosse contrôle la déshydratation et le séchage des suspensions ce qui permet d'obtenir des revêtements d'une qualité incomparable. L'objectif est de modéliser sur un plan fondamental le rôle fonctionnel des polymères en relation avec les performances en application. Dans une première partie nous étudions leurs propriétés physicochimiques, structurales et rhéologiques en solution en discutant les spécificités dues à l'architecture en brosse. Dans une seconde partie nous analysons à l'aide d'un dispositif expérimental original les propriétés de rétention d'eau apportées par les polymères. Dans une troisième partie nous étudions le séchage de suspensions de carbonate de calcium sur des substrats solides, qui conduit en général à des motifs hétérogènes dits en " anneau de café ". Nous avons découvert que les polymères en brosse à très faible concentration suppriment ces défauts de séchage de façon remarquable. Le nouveau mécanisme physique à l'¿uvre, que nous appelons effet Marangoni auto-induit, résulte des propriétés interfaciales des polymères et de leurs interactions spécifiques avec les particules de carbonate de calcium. Pour conclure nous établissons un lien entre les propriétés de rétention d'eau et l'inhibition des défauts de séchage. Nous démontrons alors le caractère générique de nos résultats en les transposant à une suspension biologique, le sang, où les polymères pourraient présenter un intérêt dans le traitement de pathologies cardiovasculaires.This work focuses on a new class of bottlebrush polymers, synthesized on an industrial scale and used as additives in colloidal suspensions for paper coatings. The bottlebrush polymer controls the dehydration and drying of the suspensions, and leads to coatings of outstanding quality. Our aim is to model the functional role of these polymers from a fundamental perspective in relation with applicative performances. In a first part we study their physicochemical, structural and rheological properties in solution, emphasizing the specificities due to the brush architecture. In a second part we implement an original experimental setup to analyze the water retention properties brought by the polymers. In a third part we study the drying of calcium carbonate suspensions on solid substrates, which in general forms to heterogeneous patterns called “coffee-rings”. We discovered that at very low concentration, bottlebrush polymers remarkably suppress these defects. We call auto-induced Marangoni effect the new physical mechanism at work. It results from the interfacial properties of the polymers and their specific interactions with calcium carbonate particles. To conclude, we establish a link between water retention properties and drying defect inhibition. We demonstrate the generic character of our results which can be transposed to a biological suspension, blood, where these polymers could be of interest for cardiovascular disease treatment
An investigation of dynamic transitions in crowded model soft colloids
Get PDFAt high packing fractions, colloidal suspensions are yield stress materials that are characterized by a solid behavior at rest and an ability to flow under a sufficient applied stress. While the formation of an organized crystalline phase may occur under certain conditions of concentration, preparation and monodipersity, most systems usually form disorganized glasses. The solid regime of hard colloids is theoretically limited by their close packing fraction (74% in the case of spheres), but the experimentally accessible limit is often the random close packing (64% for spheres) and therefore the solid regime only exist in a small range of packing fraction. The ability of soft colloids to deform and accommodate contacts (deswelling, faceting, interpenetration) extends the range of concentration at which they form a solid phase, but also complicate the evolution of the dynamic properties in this regime. As such, the systematic study of these properties requires the use of well-characterized model systems. In this work, we report on a careful examination of the rheological properties of the two main experimental model soft colloids, namely star polymers and microgel particles. In particular, we focus here on a very dense star polymer with nearly 900 short arms (5.8 kg.mol-1 per arm). We perform a series of rheological tests both in the linear and nonlinear regime. The differences between the two systems may be attributed to the main microstructural difference, the presence of dangling chains in star polymers, which are absent in microgels. We also find striking similarities, not only between the two investigated systems, but also in the data of the available literature on soft colloids, which suggests a possible universal behavior. In particular, we find that a change in the evolution of dynamic properties inside the solid regime seems ubiquitous, and we call it jamming. Several arguments point towards a transition to a regime where elasticity becomes dominated by contacts when the packing fraction reaches values very close to 1. If proven correct, this may provide a useful link between the microstructural properties (chemical composition, softness) of soft colloids and their macroscopic rheological properties (elasticity, yielding, and behavior under flow). The objective of this work is therefore to provide and disseminate reliable data to help create solid bases for the design of novel soft materials with increased performances
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
Ρεολογία, κολλαγόνο ικρώματα, αιωρήματα, ίνες αναγεννητική ιατρική μικροσκοπία, γέλες
No full textNowadays, regenerative medicine has increasingly appealing to the scientific community as it provides all the necessary supplies for the regeneration of damaged living matter, from a part of tissue, to the regeneration of an entire organ. In this thesis, we will delve into the morphology and the viscoelasticity of fibrillar collagen-based suspensions that are utilized in regenerative medicine scaffolds. Although literature emphasizes on collagen type I hydrogels, limited information is available on porous scaffolds made of lyophilized fibrillar suspensions of collagen type I despite their established utilization in regenerative medicine grafts. The raison d’ être of this thesis is to have a new perspective of collagen suspensions in terms of morphology and viscoelasticity. For this purpose, various microscopy methods such as phase contrast microscopy and cryo-TEM have been used in order to get more information on the morphology of these suspensions, as well as rheological methods to combine the imaging with the rheological response of the suspension
- …
