1,720,959 research outputs found
Inference of multivariate dependence structures in extreme value theory
No full textModelling dependence structures in high-dimensional problems of extreme events is of interest in several application areas. Current dependence models for multivariate extremes are based upon max-stable distributions and one approach is to investigate the Pickands dependence function through nonparametric estimators. In the bivariate setting, there exist several estimators while more problematic are the assumptions that must be satisfied in multivariate extremes. The aim is to briefly review an existing nonparametric inference method for estimating the Pickands function, which assume known marginal distributions, in the multivariate framework
Nonparametric estimation of the dependence among multivariate rainfall maxima
No full textMultivariate analysis of extreme values has an increasing range of applications in risk analysis, especially in the fields of environmental sciences. For example, it would be of interest for hydrologists to extract relevant information hidden in complex spatial-temporal rainfall datasets. The aim of this work is to analyse the dependence structures of weekly maxima of hourly rainfall in France recorded from 1993 to 2011. Some weather stations, initially organised in clusters, are analysed in order to summarise the dependence within all groups of seven stations. However, beyond the bivariate case, the analysis of the dependence structures for moderately high dimensional problems is still challenging. Estimation methods for assessing the extremal dependence must satisfy appropriate assumptions for guaranteeing valid results. The approach used here focuses on the nonparametric estimation of the Pickands dependence function through a specific type of Bernstein polynomial representation which ensures that all required constraints are verified
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
Emotional states in patients with cancer or with suspected oral potentially malignant disorders: a cross-sectional study in an oral medicine setting
Full text linkBackground: This cross-sectional study aims to investigate the emotional states (i.e., anxiety, depression, and stress) of 4 distinct groups of patients attending an Oral Medicine setting.
Material and Methods: four distinct subgroups of patients have been enrolled: 25 patients with OSCC (OSCC group); 25 patients with other solid tumor (ONCO group), 25 cancer patients with MRONJ (MRONJ group), 25 patients with oral potentially malignant disorder (OPMD group). Standardized assessment tools (i.e. Beck Depression Inventory (BDI) and Depression Anxiety Stress Scales-21 (DASS-21) questionnaires) were utilized to evaluate the patients’ emotional states.
Results: Among the 100 patients enrolled, 59% of whom were female, and most patients were aged between 70 and 80 years. The mean total BDI score was 16.57, and the mean total DASS-21 score was 15.32. The mean scores of the OSCC group showed moderate depression, all the other groups were classified as mild depression. The OPMD group showed a significantly higher level of anxiety.
Conclusions: Patients in the oral medicine setting may face various diseases and may develop emotional states that affect their treatment adherence. For effective management of these emotional states, the presence of a multidisciplinary team, including a psychologist, and the adoption of individualized approaches, seem to be necessary
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
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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