1,720,972 research outputs found

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

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    “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

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    We 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

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    We 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

    Author Index

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    koamabayili/VECTRON-author-checklist: VECTRON author checklist

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    We 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

    Enabling high-throughput single-cell growth measurements with parallel microchannel resonators

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    Thesis: Ph. D., Massachusetts Institute of Technology, Computational and Systems Biology Program, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 119-130).Single cells constitute a fundamental unit of biological organization, yet most laboratory techniques are unable to characterize single cell behavior and instead measure average properties of many thousands of cells. Among cellular behaviors, one of the most fundamental is growth, in which a cell turns inanimate material into biomass, which is then used to further create more biomass. However, there are few tools available to study the process of single cells growing. In this thesis, I demonstrate a new method for observing and quantifying the growth of single cells in high-throughput. This method is applicable to any cell that can grow in suspension (including bacteria, yeast, and mammalian cells), is extremely precise, and directly measures single-cell biomass accumulation. This method utilizes an array of suspended microchannel resonators (SMRs), which are microcantilevers with an interior fluidic channel through which cells flow. Cells traversing the interior fluidic channel transiently change the mass of the microcantilever, changing its resonant frequency, which we measure. Previously, it has only been possible to operate a single SMR per microfluidic chip. To enable high-throughput growth measurements, we first developed scalable hardware to operate multiple SMRs on a single chip, utilizing frequency-division multiplexing and a digitally-implemented phase-locked loop array. We call this hardware MURC - the MUltiple Resonance Controller. Outside of operating SMRs, we envision that MURC may ultimately be useful for operating many resonator-based sensors (including mass, light, or force sensors). We next developed a microfluidic chip called the serial SMR array, consisting of 10- 12 SMRs interspersed along a single long microfluidic channel. Cells are periodically weighed as they flow through this channel, typically every 30 seconds or every two minutes. The change in cell mass between when a cell enters and exits the channel tells us how fast the cell is growing. Importantly, an entire queue of cells can transit this array nearly simultaneously, yielding growth rate measurements of hundreds of cells per hour. Compared to existing methods, this system is at least an order of magnitude more precise and provides similar or higher throughput.by Nathan Cermak.Ph. D

    Water and Small-Molecule Permeation of Dormant Bacillus subtilis Spores

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    We use a suspended microchannel resonator to characterize the water and small-molecule permeability of Bacillus subtilis spores based on spores' buoyant mass in different solutions. Consistent with previous results, we found that the spore coat is not a significant barrier to small molecules, and the extent to which small molecules may enter the spore is size dependent. We have developed a method to directly observe the exchange kinetics of intraspore water with deuterium oxide, and we applied this method to wild-type spores and a panel of congenic mutants with deficiencies in the assembly or structure of the coat. Compared to wild-type spores, which exchange in approximately 1 s, several coat mutant spores were found to have relatively high water permeability with exchange times below the ∼200-ms temporal resolution of our assay. In addition, we found that the water permeability of the spore correlates with the ability of spores to germinate with dodecylamine and with the ability of TbCl₃ to inhibit germination with l-valine. These results suggest that the structure of the coat may be necessary for maintaining low water permeability.United States. Army Research Office (W911F-09-1-0286)United States. Army Research Office (W911NF-09-0001
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