1,721,235 research outputs found
G0.253+0.016 continuum image & data cubes
No full textThis dataset contains data from the ALMA project 2016.1.00949.S for G0.253+0.016 as presented in Walker et al. (2021). These data include the dust continuum, and data cubes for SiO (5-4), 13CO (2-1), and CH3CN (12-11)
Full quality images from Walker et al. (2021)
No full textRepository for the original quality uncompressed figures included in Walker et al. (2021).
Please feel free to use these, with the appropriate credit, of course
Studies of the low frequency dielectric constants and conductance of two molecular systems : carbon nanotubes and polyaromatic molecular wires
No full textThis thesis deals with two projects on the electronic properties of molecular systems. Presented first is an experiment designed to characterize the direct current charge transport characteristics of polyaromatic molecular wires, specifically oligo(phenylene ethynylene) or a five benzene ring variant 1,4-bis(2-(4-(2-(4-thioacetylphenyl)ethynyl)phenyl)ethynyl)-2,5-didodecylbenzene. The techniques and methods used to make and contact these molecular wires are given and followed up a discussion of the results and conclusions. The molecular wires were contacted by adsorbing them into a prefabricated device. A gold wire, approximately 100nm in diameter and 10µm in length was grown electrochemically with a self assembled monolayer spacer grown into the wire at 5 µm. These gold wires were contacted photolithographically resulting in a device that could be electrically contacted allowing measurement of the material in the middle of the wire. The spacer could then be removed by volatilizing away the self assembled monolayer used leaving a contacted gold wire with a nanometer scale gap at its centre. The molecular wires could then be adsorbed across this gap allowing a measurement of their properties. Using the test bed developed a measurement of resistance of oligo(phenylene ethynylene) of 44GΩ in close agreement with other groups contact atomic force microscopy methods. The second part to this thesis details the measurement of carbon nanotubes suspended in 1,2 - dichlorobenzene using impedance spectroscopy. A brief account of the theory used to understand the observed effects is presented followed by a description of the methods and results. The nanotubes were suspended in the 1,2 - dichlorobenzene at a maximum concentration of 90mg/L without a surfactant and measured across a frequency range from 107Hz to 1Hz at varying electric field strengths. This was performed in a cell that was very large compared to the nanotubes themselves and had plates with a large surface area compared to their separation to keep the field as uniform as possible. The frequency spectra were run at increasing field strengths and a drop in the real part of the impedance of the solution between the plates from 2x107Ω to 1x105Ω was observed as the electric field strength was increased. This drop in impedance did not continue as the field strength was increased further but saturated at 1x105Ω, with further decreases unobservable at the electric field strengths available to us. However it was found that the rate at which this threshold was reached depended strongly on the electric field strength and the concentration of the nanotubes in the suspension. Further work detailed in this projects show that this change in impedance is semi-permanent with no measurable decay to the original impedance observable over 8 hours. The system can be made to return towards is original state by agitation and the project shows that the more vigorous the agitation the closer to the original value of the impedance the solution becomes. This leads to the projects conclusion that chain formation or aggregation is the ultimate cause of the observed decrease in impedance although the details of the mechanism that causes this decrease in impedance remain unclear.</p
Walker (Daniel P.) La Magie spirituelle et angélique de Ficin à Campanella
No full textLaurant Jean-Pierre. Walker (Daniel P.) La Magie spirituelle et angélique de Ficin à Campanella. In: Archives de sciences sociales des religions, n°68/2, 1989. p. 310
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
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
- …
