1,721,107 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
Wear-out and breakdown of ultra-thin oxides after exposure to ionising radiation
No full textIn this work we show that electrical stresses produce HB or Soft Breakdown (SB) in ion irradiated oxides in times much shorter than in unirradiated oxides. Hence, the device life-time is substantially reduced due to the formation of localized damaged regions by ion irradiation. Even though these weak regions may drive small or negligible currents just after irradiation, they can facilitate the onset of breakdown phenomena, which can be observed for a small stress voltage applied, down to 2V, which is close to the operating voltage
Incidence of Oxide and Interface Degradation on MOSFET Performance
No full textIn this work we have studied how oxide and interface degradation affect the performance of MOSFETs with ultra-thin gate oxide, in terms of transconductance (gm), saturation drain current (Ids,SAT), and threshold voltage (Vth) before Soft Breakdown and Hard Breakdown. MOSFET transconductance and drain current decrease due to oxide traps which act as interface state reducing channel carrier mobility and enhancing the drain current noise. We found strong correlation between these traps and the well known Stress Induced Leakage Current (SILC) indicating that the same traps producing the degradation of MOSFET characteristics are those involved in SILC conductio
Soft Breakdown Current Noise in Ultra-thin Gate Oxides
No full textIn this work we studied the soft breakdown (SB) in ultra-thin gate oxides (<3 nm) subjected to constant current stress. SB current derives from the superposition of several random telegraph signals noises with different time constants and amplitudes. Such fluctuations derive from the conductance modulation of a damaged region inside the oxide layer, due to the electrical stress. We found that the current noise power density follows the 1/f(2) power law (with α between 1 and 2) over a wide range of frequency (1 Hz-100 kHz). Only at frequency smaller than 1-10 Hz a possible deviation from this low cannot be excluded. Moreover, the discrete fluctuations typical of SB are statistically independent events at least over time periods around hundreds of seconds, according to a Poisson process. This result suggest that electron trapping/detrapping in defect sites near or inside the SB conductive path can be claimed as responsible for such conductance modulation. (C) 2002 Elsevier Science Ltd. All rights reserved
Biochip electroporator and its use in multi-site, single-cell electroporation
No full textThe introduction of genetic material or molecules of biological interest into cells is a procedure with an increasing interest both for experimental and application purposes, so that electroporation is a widely used technique, but the electroporation of single adhering cells is still impaired. The present application describes an apparatus for the electroporation of any kind of cell adhering to a substrate at any stage of development, where an electrical signal can be driven and applied to a single adhering cell in culture in order to obtain its electroporation. The method to electroporate a single adhering cell with the apparatus of the invention is also described
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
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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