1,720,981 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
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
Su alcune classi di sistemi lineari positivi
Get PDFIn molti sistemi reali, le variabili di stato rappresentano delle grandezze di valore necessariamente positivo o nullo. I casi sono numerosi, e appartengono ad ambiti talvolta molto distanti tra loro.
I sistemi lineari in cui le variabili di stato assumono sempre valori non negativi sono detti positivi, e sono l'oggetto di studio di questo elaborato.
Nel primo capitolo, si descrivono le caratteristiche e le proprietà che un sistema lineare deve possedere perché possa essere definito positivo.
Nel secondo capitolo si descrivono due importanti esempi di sistemi lineari positivi, le catene di Markov ed i sistemi compartimental
Optimising MRI magnetic susceptibility mapping for the study of brain arteriovenous malformations
Get PDFMagnetic resonance imaging (MRI) magnetic susceptibility mapping (SM) enables the calculation of the magnetic susceptibility of biological tissues based on the signal phase of a gradient-recalled echo (GRE) MRI acquisition. Because deoxygenated haemoglobin is paramagnetic, SM can be used to calculate the χ of venous blood which is proportional to venous oxygen saturation (SvO2). In this thesis, I investigated the feasibility of SM for the study of brain arteriovenous malformations (AVMs). AVMs are congenital vascular anomalies characterised by arteriovenous shunting through a network of coiled and tortuous vessels. Because of this anatomy, the venous drainage of an AVM contains high-pressure mixed arterial and venous blood. I investigated whether SM could detect any resulting increased oxygenation in the draining veins. Using numerical simulations and healthy volunteer data, I focussed on optimising the acquisition and processing of GRE phase data to achieve the best possible accuracy and precision for venous SM. I showed that acquiring multi-echo versus single-echo GRE data led to more accurate and precise susceptibility, and that combining the signal from multiple echoes before applying Laplacian-based phase unwrapping or background field removal increased the susceptibility’s accuracy. Based on healthy volunteer and patient data (before and after gamma knife radiosurgery (GKR)) I investigated the feasibility of SM of brain AVMs and the information provided by venous susceptibility on AVM pathophysiology. I showed that an AVM was detectable on a susceptibility map and that the AVM draining pattern had a significantly higher SvO2 compared to healthy veins. Flowing spins in blood cause an additional susceptibility-independent component in the GRE signal phase. Because clinical multi-echo GRE protocols, including the one developed here to study brain AVMs, do not compensate for flow-induced dephasing, I investigated the effect of flow compensation on venous susceptibility and SvO2 measurements and found only a minimal effect
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