1,720,963 research outputs found
Unraveling gelation kinetics, arrested dynamics and relaxation phenomena in filamentous colloids by photon correlation imaging
Get PDFISSN:1744-683XISSN:1744-6848ISSN:1744-684
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
Sviluppo di un apparato di correlazione ottica per lo studio della sedimentazione di particelle in presenza di gradienti termici
No full textLAUREA MAGISTRALETermoforesi e sedimentazione sono due ambiti del mondo fisico di grande interesse e di grande sfida. Un loro studio più approfondito, sotto i punti di vista teorico e sperimentale, può condurre a grandi passi in avanti nel mondo scientifico e tecnologico. Lo sviluppo di nuove tecniche ottiche di indagine, e in particolare della Differential Dynamic Microscopy, ha permesso di combinare i vantaggi dell’analisi microscopica e dello scattering e di realizzare così sperimentazioni con strumenti ottici semplici ma potenti. Il presente lavoro di tesi si è focalizzato sulla realizzazione di un nuovo apparato sperimentale che consenta l’analisi di campioni di natura colloidale in diversi ordini di grandezza che li caratterizzano. In particolar modo, diverse configurazioni dello strumento ottico permettono di effettuare indagini che vanno dalla scala micrometrica della particella (mediante la configurazione microscopica) alla scala caratteristica della cella presa in esame (nell’ordine di grandezza dei millimetri o dei centimetri). In questa seconda casistica, approfondita nel contesto del presente lavoro, è possibile risalire, mediante l’analisi dei campi speckle con opportune tecniche di correlazione, al comportamento delle particelle senza la necessità di avere uno strumento ottico la cui capacità risolutiva arrivi fino al loro ordine di grandezza. Secondo i principi ora esposti sono quindi state analizzate delle dispersioni colloidali di polistirene (PS), di MFA e di PMMA poste in due diverse celle: una orizzontale e spessa 600 μm, l’altra verticale e spessa 5 mm. Entrambe le celle erano dotate di strumenti di controllo e monitoraggio della temperatura, con la possibilità di instaurare dei gradienti termici e di studiare con le tecniche di correlazione il comportamento dei campioni. Sono quindi stati analizzati i campi di moto instauratisi all’interno delle celle e, nel caso della cella verticale, è stata valutata la loro interazione con i fenomeni di sedimentazione.Thermophoresis and sedimentation are two areas of physics of great interest and great challenge. A deeper analysis of these phenomena, under the theoretical and experimental points of view, can lead to a great scientific and technological advance. The development of new optical techniques, and in a particular way of the Differential Dynamic Microscopy, allowed combining the advantages of both microscopic and scattering analysis, in order to realize new scientific experiments with simple and powerful optical instruments. This thesis work has analyzed the construction of a new experimental setup, which allows analyzing colloidal samples in several order of magnitude. In particular, multiple configurations of the optical instrument allow carrying out investigations ranging from the micrometre scale (using the microscopy configuration) to the characteristic scale of the cell used for the experiment, whose order of magnitude is in the order of millimeters or centimeters. In this second case, which has been analyzed in this work, it’s possible to go back, by the analysis of speckle fields with appropriate correlation techniques, to the behaviour of the particles, whose order of magnitude is below the resolution limit of the optical instrument. Colloidal samples of polystyrene (PS), of MFA and of PMMA have been analyzed in two different configurations, with the techniques above mentioned. The first cell has been used in horizontal configuration and is 600 μm thick, while the second one has been used in vertical configuration and is 5 mm thick. The temperature of the two cells has been monitored and controlled and thermal gradients have been applied to the system. The behaviour of the samples has been analyzed with correlation techniques and the velocity field of convective rolls that have grown up has been analyzed with digital programs. In the vertical cell the interaction between the convective rolls and the sedimentation processes have been studied
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
