1,721,057 research outputs found
Impact of Slave Clock Internal Noise on Allan Variance and Root Mean Square Time Interval Error Measurement
No full textHamamatsu, Japa
Optical coherence tomography, frequency-doubling technology, and colour Doppler imaging in ocular hypertension
No full textPURPOSE: To study in ocular hypertension (OH) the retinal nerve fibre layer (RNFL) with optical coherence tomography (OCT) and the neuronal function with frequency-doubling technology (FDT) to assess which of the two methods was more sensitive in detecting early glaucomatous damage. Furthermore, a colour Doppler imaging (CDI) of the optic nerve was carried out to highlight any correlation with RNFL thickness and FDT abnormality. MATERIALS AND METHODS: We enrolled 28 ocular hypertensive patients who underwent OCT of the RNFL and FDT. Moreover, we performed a CDI of the ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary arteries (PCAs). RESULTS: The patients with OH following OCT revealed a significant thinning in the RNFL as compared to the control group only in the inferior quadrant: 122.250+/-14.091 vs131.750+/-10.729 mum (P<0.045). As regards FDT, there was a significant difference between the two groups only for pattern standard deviation (PSD): 3.873+/-1.488 vs1.938+/-0.704 dB (P<0.044). In OH and in the control group, CDI resistance index (RI) in the OA was 0.768+/-0.012 vs0.745+/-0.019 (P<0.022), in the CRA was 0.66+/-0.012 vs0.645+/-0.019 (P<0.032), and in PCAs was 0.673+/-0.039 vs0.622+/-0.012 (P<0.037). The OCT had a sensitivity of 83% but only in the inferior RNFL quadrant. The FDT-PSD revealed a sensitivity of 85%. CONCLUSIONS: Both FDT and OCT detect early glaucomatous damage with a slightly superior sensitivity of FDT vsOCT. The CDI measurements suggest that circulatory abnormalities may have a role in the development of OCT and FDT damage.
PMID: 16888642 [PubMed - in process
An Analysis of Terrorist Attacks on Soft and Hard Targets in the Period 2000-2019
Full text linkWith the aim of characterising the evolution of the phenomenon of terrorist attacks in the 20 years since 9/11, this paper conducts a broad analysis of terrorist events from 2000 to 2019, based on information made available by the Global Terrorism Database (GTD). The first part of the document illustrates the evolution of terrorist attacks worldwide, while the second part focuses on the type of targets favoured by terrorists. As a key result of the analysis, it will be shown that in recent years many attacks have been directed against simple public and private buildings, targeting and killing individuals, typically civilians. These types of targets have been referred to in the literature as soft targets, as opposed to the term hard targets or hardened structures, government, military, police and intelligence buildings and sites. In the work, specific definitions of soft target and hard target related to GTD information fields are proposed and evaluated over the period 2000-2019. Furthermore, detailed items of the terrorist targets, such as houses, schools, universities, restaurants, theatres etc., were considered and analysed. The evidence obtained provides an up-to-date view of terrorists' recent approaches to selecting targets and conducting attacks. The understanding of the evolution of these approaches can allow for better organisation of future prevention and protection of potential soft and hard targets
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
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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