1,720,957 research outputs found
A 1 GS/s sampling digitizer designed with interleaved architecture (GSPS) for the LaBr3 detectors of the FAMU experiment
No full textA fast continuous sampling digitizer has been designed to acquire fast scintillating detector signalfrom cerium activated lantanum bromide (LaBr3(Ce)) scintillation crystal. These are foreseenin the FAMU experiment which is aimed at spectroscopic measurements of muonic hydrogen,possibly providing insights into the so-called proton radius puzzle. The board, named GSPS,is implemented as an FMC mezzanine which hosts two off-the-shelf sampling ADC used in in-terleaved timing architecture, achieving a 1 GS/s sampling rate (with a 12-bit nominal accuracyover the first Nyquist interval of frequencies, ranging from DC to 500 MHz). Interleaved tech-nique allowed us to keep both lower production costs and simple acquisition system avoidingcomplex interface protocols like JESD204. The board will be described; the test setup and theused methodology to characterize the device will be explained; the achieved performances willbe shown and discussed. In particular it will be pointed out how the two interleaved ADCs can becalibrated in order to get the best performance. The different contributions to both noise and dis-tortion affecting the device will be analyzed applying general techniques for high-sampling-speedcontinuous ADCs. Lastly, future improvements will be introduced: in particular, the solutions weforesee to get a effective number of bits of about 10 over the whole first Nyquist interval will beenlightened
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
Imaging characterization of a multi-energy CT with quasi-monochromatic X-ray source
Full text linkA new multi-energy computer tomographic system for small animals (MECT) was developed - and is now operative - with a quasi-monochromatic X-ray source. The system brings together two important features: the possibility to scan small animal with quasi-monochromatic X-ray beams and the possibility to select a multiple energy algorithm for the imaging reconstruction. The medical imaging with monochromatic beams is in fact the new frontier since it allows a new way to visualize selectively different tissues by injecting contrast medium but also without using it. Indeed, an Alvarez-Macovsky like algorithm can enhance the sensitivity of the imaging system to a contrast medium provided with a K-shell binding energy (for example, the iodine has a K-edge at 33.2 keV and the measured sensitivity enhancement is of about 10 times). Moreover, using monochromatic X-ray beams with different energies, it is possible to measure, point-by-point, the tissue density, the electron density and the effective atomic number, exalting the physicochemical information of tissues. These data are all available with a patient scanning using two (or better three) quasi-monochromatic X-ray beams at different energies. However, with a new reconstruction algorithm based on three different energy beams, the so-called projection artifact (due to not homogeneous density of the background) can be corrected, making the tissues separation and the visualization of very low concentration of contrast medium available. This facility and the new reconstruction algorithm, was developed to study, on small animals, the possibility to introduce new methods for the earlier diagnosis of the tumors, by exalting the precancerous tissue changes as, for example, the neoangiogenesis. Aim of this work is to discuss the imaging proprieties of the quasi-monochromatic CT, using both the images of dedicated phantom and in-vivo images of small animals. © 2011 IEEE
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
On field spectrometry for diagnostic X-ray beams: Comparison between innovative devices
No full textThe knowledge of X-ray beam spectrum should be of great interest for the optimization of diagnostic procedures, allowing to reduce the patient dose improving the image quality. In fact, only the spectrometric analysis permits a complete characterization of the photonic beam both under qualitative and quantitative aspects enabling attenuation studies and quality parameters evaluation. © 2011 IEEE
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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