1,721,008 research outputs found
Likeness-Based Detection of Sleep Slow Oscillations in Normal and Altered Sleep Conditions: Application on Low-Density EEG Recordings
No full textSleep slow oscillation (SSO) is a common EEG pattern of spontaneous activity during nonrapid eye movement sleep. A new method for detecting SSOs is presented and compared to previous canonical methods. The main result of this research is that for the first time an extensive SSO analysis is applied to clinical EEG montages, based on low-density EEG recordings. The proposed method gives positive indications about its effectiveness also for altered sleep, extending the SSO analysis to extreme cases, and thus, opening a new front for investigating pathophysiological correlates of sleep disorders
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
Actigraphic sleep detection: an artificial intelligence approach
Get PDFObjective: Polysomnography is the gold standard for sleep monitoring, despite its many drawbacks: it is complex, costly and rather
invasive. Medical-grade actigraphy represents an acceptably accurate alternative for the estimation of sleep patterns in normal, healthy
adult populations and in patients suspected of certain sleep disorders. An increasing number of consumer-grade accelerometric
devices populate the “quantified-self” market but the lack of validation significantly limits their reliability. Our aim was to prototype and
validate a platform-free artificial neural network (ANN) based algorithm applied to a high performance, open source device (Axivity
AX3), to achieve accurate actigraphic sleep detection. Methods: 14 healthy subjects (29.35 14.40 yrs, 7 females) were
equipped for 13.3 2.58 h with portable polysomnography (pPSG), while wearing the Axivity AX3. The AX3 was set to record 3D
accelerations at 100 Hz, with a dynamic range of 8 g coded at 10 bit. For the automatic actigraphy-based sleep detection, a 4 layer
artificial neural network has been trained, validated and tested against the pPSG-based expert visual sleep-wake scoring.
Results: When compared to the pPSG gold standard scoring, the ANN-based algorithm reached high concordance (85.3 0.06%),
specificity (87.3 0.04%) and sensitivity (84.6 0.1%) in the detection of sleep over 30-sec epochs. Moreover there were no
statistical differences between pPSG and actigraphy-based Total Sleep Time and Sleep Efficiency measurements (Wilcoxon test).
Conclusions: The high concordance rate between ANN-actigraphy scoring and the standard visual pPSG one suggests that this
approach could represent a viable method for collecting objective sleep-wake data using a high performance, open source actigraph
Low-density EEG study of dynamic properties of cortical sleep slow oscillation in humans: perspectives for clinical applications
No full textLow-density EEG study of dynamic properties of cortical sleep slow oscillation in humans: perspectives for clinical applications
No full text
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
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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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