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Instrument development and a total scattering investigation of aqueous magnesium sulfate
No full textNon-crystalline materials, such as amorphous and glassy phases, and aqueous systems, remain an understudied yet important class of condensed materials. Many techniques can be used to enable structure elucidation of these materials, but few can match the application of total scattering and subsequent fitting of the observed data with atomistic models. This work will examine the feasibility of using a laboratory-based single crystal diffractometer for total scattering experiments that previously would often have required synchrotron radiation. The instrument has a rather unique curved image-plate detector that is ideal for collecting very low noise data over a large scattering angle. When a silver tube is fitted this enables a theoretical Qmax of 22.4 Å-1 to be reached and data collected rapidly. Suitable data collection strategies and data reduction processes were evaluated through the study of a number of standard materials ranging from crystalline and nanocrystalline to amorphous and aqueous. The quality of the data and refined models were then evaluated. Using X-ray data from this novel setup, in combination with neutron scattering data, it was possible to use an empirical potential structure refinement (EPSR) approach to model the structural features of an aqueous sample of magnesium sulfate. Combining the isotopically substituted neutron data with the high quality in-house X-ray data enabled an extensive study of the structural features that exist within this aqueous salt. The structural features observed via this methodology highlight both the short-range ordering (first shell), similar to that found in previous studies, but also a distinct medium-range order describing the intermolecular structure not previously discussed in the literature. This highlights both the power of the refinement technique but also the capabilities of the laboratory X-ray scattering instrument. With this initial study as a foundation, it was possible to use just X-ray data to confidently study changes to the structure induced by changing conditions. Firstly, the effects of varying temperature on a constant concentration solution were investigated and found to have minimal effect. Secondly varying temperature was used as a method of stabilising higher concentrations above the ambient saturation limit to begin weaving a narrative of how the structure changes as a function of concentration with the aim of probing conditions as the crystallisation point is approached. In these studies, large, more structured features were observed that resembled those found in the various crystalline phases of hydrated magnesium sulfate. EPSR has proven to be a very powerful technique, and in combination with the unique laboratory X-ray scattering instrument, has examined an aqueous structure in more detail than previous studies
Dataset: Instrument Development and a Total Scattering Investigation of Aqueous Magnesium Sulfate
No full textData to accompany the Southampton University Doctoral thesis titled 'Instrument Development and a Total Scattering Investigation of Aqueous Magnesium Sulfate'
Data included is RAW scattering data, processed scattering data and various refinements. </span
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
Data for 'Advantages of a curved image plate for rapid laboratory-based X-ray total scattering measurements'
No full textThis data set supports the publication:
Advantages of a curved image plate for rapid laboratory-based x-ray total scattering measurements: Application to pair distribution function analysis
Review of Scientific Instruments 92, 043107 (2021); https://doi.org/10.1063/5.0040694</span
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
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