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Digital field programmable gate array-based lock-in amplifier for high-performance photon counting applications
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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
Microchips and Single-Photon Avalanche Diodes for DNA Separation with High Sensitivity
No full textModern techniques for DNA and protein analysis and separation rely on measurements of LIF and face a trend toward employing progressively smaller samples. The currently employed detectors that provide the required ultrahigh sensitivity, e.g. photomultiplier tubes (PMTs), are bulky and/or costly and delicate, whereas a key issue for the development of compact and economical instruments is the availability of miniaturized, inexpensive, and ultrasensitive photodetectors. The planar epitaxial silicon singlephoton avalanche diodes (SPADs) combine the typical advantages of microelectronics (miniaturization, ruggedness, low voltage, low power, low cost, etc.) with high sensitivity, even better than that of PMTs. The suitability of such SPADs to microchip CE has been here ascertained by developing a new apparatus with dual-wavelength LIF detection. The apparatus has been experimented in studies on the EOF suppression and on the coating stability and tested in rapid sizing of DNA fragments. The experimental results obtained in the separation of Cy5-labeled oligonucleotide demonstrate sensitivity better than 3 pM, which corresponds to less than 100 fluorescent molecules in the 50 pL illuminated volume
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
Monolithic matrix of 50μm silicon SPAD detectors
No full textA 48-element monolithic matrix detector, designed for easy and efficient coupling to input optical systems, has been fabricated and tested. The pixels are single photon avalanche diodes (SPAD) with 50 μm diameter, ordered in a 8x6 array with 240 μm pitch. The photon detection efficiency is remarkably uniform over the array, with 48% peak value at 530 nm and better than 30% value over all the visible range. Low dark counting rate (DCR) is obtained in operation at moderately low temperature (-15 C with Peltier element cooling): the individual pixel DCR is 60 cps for about 40% of the elements and is below 5700 cps in the rest of the array. It was verified that the afterpulsing probability is below 1% and that the optical crosstalk probability between elements is lower than 0.002
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
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