1,720,979 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
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
RAYLEIGH-BÉNARD INSTABILITY OF THE POWER-LAW FLUID FLOW IN A POROUS MEDIUM: NUMERICAL AND EXPERIMENTAL ANALYSIS
No full textThe thermal instability of fluid saturated porous media is a topic extensively investigated in the last decades. The scientific community has focused its efforts especially on the study of the stability of Newtonian fluids [1]. The investigation of the stability of non-Newtonian fluids is a topic poorly explored. Only a few papers extended the results reported by Horton and Rogers [2], Lapwood [3], and Prats [4] to non-Newtonian fluids.
The aim of this paper is to further develop the work done by Barletta and Nield [5] with reference to a fluid characterised by a temperature-dependent consistency index. A two dimensional fluid saturated horizontal porous layer is thus investigated with respect to the onset of thermal instability. The porous layer is subject to a horizontal throughflow and it is heated from below as in the classical Prats problem. A power-law fluid is considered. An extended Darcy's law and Oberbeck-Boussinesq approximation are assumed while the solid phase and the fluid phase are in local thermal equilibrium. A temperature-dependent viscosity model is employed. The porous layer is impermeable. Two different temperatures are imposed, with heating from below. The problem here described is investigated both numerically and experimentally.
From the theoretical viewpoint, the stationary basic throughflow is perturbed by plane wave disturbances. A linear stability analysis is thus carried out using the normal mode method. The eigenvalue problem obtained is solved numerically by means of the Runge-Kutta method coupled with the shooting method. The neutral stability curves are obtained along with the critical values of the stability parameters that identify the threshold for the onset of thermal instability.
The experimental configuration employed for the analysis of this problem consists of a Hele-Shaw cell. The cell is composed by an aluminium frame with a central window obtained by using two polycarbonate plates that ensure the optical access to the cell for velocity measurements. These measurements are performed with a Particle Image Velocimetry (PIV). The isothermal boundary conditions are obtained by circulating water for the hot lower boundary, and by circulating coolant for the cold upper boundary. Two free surface wells are connected to the cell, allowing injection and extraction of fluid in order to generate a constant horizontal flow. A syringe pump is used to inject the requested discharge inside the cell. The pump discharge is modulated by a Proportional Integral Derivative (PID) control system. In order to obtain a purely vertical temperature gradient, the cell is thermally insulated in all its components with foam rubber and thermal insulating tape.
The experimental investigation poses several challenges, such as the choice of tracers for PIV measurements, the discrimination between horizontal velocity components induced by convection and the imposed throughflow, the presence of hysteretic effects in cell appearance and disappearance, and the correct reproduction of shear-thickening behaviour
The effect of local thermal non-equilibrium on the onset of thermal instability for a metallic foam
Full text linkMixed convection in metallic foams modeled with Darcy's law under local thermal non-equilibrium conditions is investigated, where the solid phase thermal conductivity is assumed to be infinitely larger than its fluid phase counterpart. A linear and modal stability analysis was employed to evaluate the convective and absolute instability thresholds as well as their respective cell patterns. This analysis indicates that local thermal non-equilibrium always has a stabilizing effect and the spanwise uniform mode is always the most unstable. At the onset of convective instability, however, the number of equally unstable cell patterns increases with both the aspect ratio and the local thermal non-equilibrium strength
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
- …
