1,720,981 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
Fabrication of plastic microchips by hot embossing.
No full textPlastic microchips with microchannels (100 μm wide, 40 μm deep) of varying designs have been fabricated in polymethylmethacrylate by a hot embossing process using an electroform tool produced starting with silicon chip masters. Hot-embossed chips were capped with a polymethylmethacrylate top using a proprietary solvent bonding process. Holes were drilled through the top of the chip to allow access to the channels. The chips were tested with fluid and shown to fill easily. The seal between the top of the chip and the hot embossed base was effective, and there was no leakage from the channels when fluid was pumped through the microchannels. The chips were also tested with a semen sample and the plastic chip performed identically to the previous silicon–glass and glass versions of the chip. This microfabrication technique offers a viable and potentially highvolume low cost production method for fabricating transparent microchips for analytical applications
Integrated cell isolation and polymerase chain reaction analysis using silicon microfilter chambers.
No full textWhite blood cells are isolated from whole blood in silicon–glass 4.5-ml microchips containing a series of 3.5-mm feature-sized ‘weir-type‘ filters, formed by an etched silicon dam spanning the flow chamber. Genomic DNA targets, e.g., dystrophin gene, can be directly amplified using the polymerase chain reaction (PCR) from the white cells isolated on the filters. This dual function microchip provides a means to simplify nucleic acid analyses by integrating in a single device two key steps in the analytical procedure, namely, cell isolation and PC
Surface effects on PCR reactions in multichip microfluidic platforms
No full textWe evaluated the compatibility of several common plastics, commercially available plastic tubing and disposable syringes which might be useful in the construction of microfluidic platforms with respect to the polymerase chain reaction (PCR). A simple and inexpensive plastic test module was constructed in order to evaluate some of the construction plastics. We also investigated the effect of addition of PEG 8000 to PCR reaction mixtures on the compatibility of materials. These studies identified several common plastics, plastic tubing, and disposable syringes which were compatible with the PCR reaction
Micropillar array chip for integrated white blood cell isolation and PCR
No full textWe report the fabrication of silicon chips containing a row of 667 pillars, 10 by 20 mm in cross-section, etched to a depth of 80 mm with adjacent pillars being separated by 3.5 mm. The chips were used to separate white blood cells from whole blood in less than 2 min and for subsequent PCR of a genomic target (eNOS). Chip fluid dynamics were validated experimentally using CoventorWare TM microfluidic simulation software. The amplicon concentrations were determined using microchip capillary electrophoresis and were >40% of that observed in conventional PCR tubes for chips with and without pillars. Reproducible on-chip PCR was achieved using white blood cell preparations isolated from whole human blood pumped through the chip
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
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