134,520 research outputs found
Multivariate Markov-switching ARMA processes with regularly varying noise
No full textThe tail behaviour of stationary R^d-valued Markov-Switching ARMA processes driven by a regularly varying noise is analysed. It is shown that under appropriate summability conditions the MS-ARMA process is again regularly varying as a sequence. Moreover, the feasible stationarity condition given in Stelzer (2006) is extended to a criterion for regular variation. Our results complement in particular those of Saporta (2005) where regularly varying tails of one-dimensional MS-AR(1) processes coming from consecutive large parameters were studied
Influence of BMI, gender, and sports on pain decrease and medication usage after facet–medial branch neurotomy or SI joint lateral branch cooled RF-neurotomy in case of low back pain: original research in the Austrian population
No full textWolfgang Stelzer,1 Valentin Stelzer,1 Dominik Stelzer,1 Monika Braune,1 Christine Duller2 1Medizinisches Zentrum SchmerzLOS Linz and Baden/Vienna, Vienna, 2Johannes Kepler University Linz, Linz, Austria Purpose: This retrospective original research was designed to illustrate the general outcome after radiofrequency (RF) neurotomy of lumbar medial branch (MB) and posterior ramus of the sacroiliac joint of 160 patients with chronic low back pain (LBP) 1, 6, and 12 months after treatment.Methods: Visual Analog Scale (VAS) 0–10 pain scores, quality of life, body mass index (BMI), medication usage, and frequency of physical exercise/sports participation (none, 1–3×/week, more) were collected before the procedure, at 1 month post procedure (n=160), and again at 6 (n=73) and 12 months (n=89) post procedure.Results: A VAS decrease of 4 points on a 10-point scale (from 8 to 4) in the overall group was seen after 6 months and of 4.5 after 12 months. Lower medication usage was reported, with opioids decreased by 40% and nonsteroidal anti-inflammatory drugs (NSAIDs) by 60%. Decreased pain lasted for 12 months. Significantly better outcomes were reported by patients with BMIs <30. No gender-specific differences occurred in the reported decrease in VAS. Analysis of the “no-sports” group versus the more active (1–3 times weekly sports) group showed a better pain decrease after 1 year in the active group.Conclusion: The data suggest RF treatment for chronic LBP that can lead to long-term improvement. Patients with a BMI >30 are less likely to report decreased pain. The better long-term pain relief in the sports participating group is a motivation for the authors to keep the patients in motion. Keywords: radiofrequency, low back pain, BMI, sacroiliac joint, gender, sports, cooled RF neurotom
'Poison on, monsters!’: Female Poisoners in Early Modern Roman Tragedies
No full textThis essay investigates the representation of the Julio-Claudian veneficae in early modern English drama through the analysis of three plays— Matthew Gwinne’s Nero (1603), Thomas May’s Tragedy of Julia Agrippina (1639), and Nathanael Richards’s Messalina (1640)
Cultural and Genre Markers in Lucy Hutchinson's Order and Disorder
No full textOrder and Disorder, since its attribution to Lucy Hutchinson (1620-1681) at the turn of the twenty-first century, has been hailed as Eve’s version of Genesis, as the first epic poem by an English woman, even conjuring a Paradise Lost written by “Judith Milton”. More recently, scholars have questioned the genre of this unfinished poem in 20 cantos, moving it from the category of epic to that of the biblical meditation and paraphrase. Hutchinson’s work expresses what Elizabeth Scott-Baumann (2013, 197) has termed a “poetics of not knowing”: negotiating the need to remain faithful to the Biblical narrative and a desire to express the ineffable, Hutchinson promises her readers in the Preface that they will find “nothing of fancy”, “no elevations of style, no charms of language”, and yet, the author resorts to an array of techniques to sing the sublimity of the “mystic wonders” with which her “ravished soul” has been “fire[d]” (1.1-2). Such devices include gendered modesty tropes; apophasis; potentially subversive conditionals and subjunctives; a complex intertextuality with authors ranging from Virgil and Lucretius to Du Bartas, Edmund Spenser, and even Shakespeare, and a complication of the readerly experience via paratextual glosses. This essay wishes to revisit the assessment of such techniques and suggest that Hutchinson weaves in her poem different markers to voice the varying degrees of her “endless admiration” (1.15)
MeSH term explosion and author rank improve expert recommendations
Get PDFInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Mixing conditions for multivariate infinitely divisible processes with an application to mixed moving averages and the supOU stochastic volatility model
No full textWe consider strictly stationary infinitely divisible processes and first extend the mixing
conditions given in Maruyama [18] and Rosinski and Zak [23] from the univariate to the
d-dimensional case.
Thereafter, we show that multivariate Lévy-driven mixed moving average processes
satisfy these conditions and hence a wide range of well-known processes such as superpositions
of Ornstein-Uhlenbeck (supOU) processes or (fractionally integrated) continuous
time autoregressive moving average (CARMA) processes are always mixing. Finally,
mixing of the log-returns and the integrated volatility process of a multivariate supOU
type stochastic volatility model, recently introduced in Barndorff-Nielsen and Stelzer [5],
is established
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
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
Get PDFBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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