1,721,112 research outputs found
Experimental performance comparison between CMUT and piezoelectric probes in measuring backscatter anisotropy
No full textQuantitative ultrasound (QUS) techniques based on the parameterization of the backscatter coefficient (BSC) generally assume that the tissue under consideration is homogeneous and isotropic. However, tissues such as flowing blood aggregates and biceps muscles exhibit anisotropy in the BSC and/or attenuation coefficient. Recent works have proposed the measurement of anisotropic QUS parameters by using the reference phantom method when performing conventional imaging modalities, i.e. beamsteering or plane wave, with linear array transducers. One limitation remains the maximal angle to which the BSC can be measured, which is determined by the probe steering capability that depends on element directivity (array design) and crosstalk (transducer technology). The aim of this work is to compare the performance of a Capacitive Micromachined Ultrasonic Transducer (CMUT) and a piezoelectric probe in measuring backscatter anisotropy. Ultrasonic experiments were conducted on two comparable probes, i.e. the commercial piezoelectric probe LA435 (ESAOTE, Florence, Italy) (fc=12.5 MHz, 80% FBW, pitch=0.2 mm), and the HF3 CMUT prototype probe (fc=12.5 MHz, 100% FBW, pitch=0.2 mm), using the ULA-OP open ultrasonic system. In vitro measurements of the BSC using the focused beam steering imaging strategy were performed on an anisotropic tissue-mimicking phantom at different insonification angles ranging from 0° to 20°. The results show how the limited steering capabilities of linear probes could affect the measurement of BSC, and in general the anisotropic QUS parameters, bringing into discussion their consideration in the development of experimental strategies for the assessment of tissue anisotropy
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
Ebrei e non ebrei nell'universo concentrazionario di Tadeusz Borowski
No full textJews and Gentiles in Borowski's Concentration universe
The Polish writer Tadeusz Borowski (1922-1951) was a political prisoner detained in several Nazi extermination camps (Auschwitz, Natzweiler-Dautmergen, Dachau-Allach) from the spring of 1943 to May 1945. Soon after his liberation, he wrote several tales, short stories and poems, in which he described Warsaw during its ferocious Nazi occupation as well as the day-to-day life in the camps. Borowski's descriptions of the spaces and functions of the camps, which he portrays as a dystopic projection of XX century fordist-capitalist society, set him apart from other Holocaust witnesses and writers. To give the reader a picture of this enormous economic, sociological and psychological experiment, Borowski allows his main character and narrator Tadzio to access the emblematic places of the Auschwitz-Birkenau "metropolis." As a result, even the narrator and the other prisoners appear dystopically shaped by the annihilating system in which they live. My paper analyzes the narrative mechanisms which describe the image of Jews - the Nazi Caste system' pariahs - in the concentration camps
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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