1,721,063 research outputs found
Optimal portfolio for HARA utility functions when risky assets are exponential additive processes
No full textIn this paper, we analyse a market where the risky assets follow exponential
additive processes, which can be viewed as time-inhomogeneous
generalizations of geometric Levy processes. In this market we show
that, when an investor wants to maximize a CRRA utility function of
his/her terminal wealth, his/her optimal strategy consists in keeping
proportions of wealth in the risky assets which depend only on time
but not on the current wealth level or on the prices of the risky
assets. In the time-homogeneous case, the optimal strategy is to keep
constant proportions of wealth, a result already found by Kallsen which
extends the classical Merton’s result to this market. While the onedimensional
case has been extensively treated and the multidimensional
case has been treated only in the time-homogeneous case Callegaro
and Vargiolu (2009), Kallsen (2000), and Korn et al. (2003) to the
authors’ knowledge this is the first time that such results are obtained
for exponential additive processes in the multidimensional case. We use
these results to show that the optimal solution in the presence of jumps
has the form of the analogous one without jumps but with the asset
yields vector reduced by suitable quantities: in the one-dimensional
case, we extend a result by Benth et al. (2001). We conclude with four
examples
Is time to change to halogenated drugs in cardiac surgery, what do we have to do with propofol?
No full textThere is initial evidence, at least in cardiac surgery, that total intra-venous anesthesia (usually a propofol-based total intravenous anesthesia) is associated with an increased mortality when compared to an anesthetic plan including a halogenated anesthetics. The cardiac protective properties of halogenated agents (desflurane, isoflurane and sevoflurane) have not been confirmed in non-cardiac surgery and mixed results exist for patients admitted in postoperative intensive care units. This article summarizes the papers with the most impressive findings in favor of halogenated anesthetics, but it recognizes that, at the same time, there is no evidence based medicine against the use of propofol, highlighting the need for large randomized trials that should focus on survival
Extracorporeal membrane oxygenation and lethal diseases: A new perspective
No full text"Lethal cancer and chronic untreatable viral disease with life threatening consequences are among the major burden for morbidity and mortality in the western world. A large number of resources are employed every year in identification of new drugs to treat this condition. A remarkable percentage of resources are wasted for safety concerns about possible acute cardiac or pulmonary toxicity of the new identified compounds, that are rejected without further development even when promising. ExtraCorporeal Membrane Oxygenation (ECMO) is an established technique to support and replace cardio-pulmonary function that underwent rapid technologic improvement in the last years, resulting in reduced complication rate. ECMO has been used with success to treat acute life-threatening cardiac and pulmonary toxicity. Our hypothesis is that the new ECMO technological improvement could make this technique available to other setting, such as lethal cancer and infectious diseases, where it can provide a safe base to overwhelm acute cardiac and pulmonary toxicity of chemotoxic drugs and techniques. New drugs and old promising compounds rejected for toxicity could thus be re-introduced and employed, opening a new scenario in the treatment of life-threatening diseases. (C) 2013 Elsevier Ltd. All rights reserved.
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
The attractiveness of network meta-analysis: a comprehensive systematic and narrative review
No full textNetwork meta-analysis provides a global estimate of comparative treatment effectiveness combining both direct and indirect evidence. In the past decade, the medical literature has witnessed a rapid increase in the possibility to combine evidence from different treatment comparisons. This opportunity is attractive for clinicians since their major concern is to identify the single best available treatment. In addition, despite the sudden increase of publications concerning network meta-analysis, only a limited number focus on methodological and statistical aspects, and many issues remain unclear. The aim of our work was to explore and emphasize the potential attractiveness of network meta-analyses. We performed a systematic and narrative review (last updated on April 15, 2014) in order to assess the scholarly diffusion of network meta-analyses. The following data were collected: author identification, year and journal of publication, PubMed index, number of treatments and studies included, characteristics of network configuration, nature of primary outcome, clinical indication, type of intervention investigated and medical area. Since 2003 there has been an exponential increase in the number of published network meta-analyses. Out of 340 articles included according to our selection criteria, encompassing 248 treatment networks, cardiovascular and pulmonary diseases were the most prevalent topics, with an average of 5 treatments being compared stemming from an average of 10 controlled trials. In conclusion, network meta-analyses are becoming increasingly attractive as they offer a comprehensive framework for decision-making. Whether they will also contribute to improvements in patient outlook remains to be proven
The attractiveness of network meta-analysis: a comprehensive systematic and narrative review
No full textNetwork meta-analysis provides a global estimate of comparative treatment effectiveness combining both direct and indirect evidence. In the past decade, the medical literature has witnessed a rapid increase in the possibility to combine evidence from different treatment comparisons. This opportunity is attractive for clinicians since their major concern is to identify the single best available treatment. In addition, despite the sudden increase of publications concerning network meta-analysis, only a limited number focus on methodological and statistical aspects, and many issues remain unclear. The aim of our work was to explore and emphasize the potential attractiveness of network meta-analyses. We performed a systematic and narrative review (last updated on April 15, 2014) in order to assess the scholarly diffusion of network meta-analyses. The following data were collected: author identification, year and journal of publication, PubMed index, number of treatments and studies included, characteristics of network configuration, nature of primary outcome, clinical indication, type of intervention investigated and medical area. Since 2003 there has been an exponential increase in the number of published network meta-analyses. Out of 340 articles included according to our selection criteria, encompassing 248 treatment networks, cardiovascular and pulmonary diseases were the most prevalent topics, with an average of 5 treatments being compared stemming from an average of 10 controlled trials. In conclusion, network metaanalyses are becoming increasingly attractive as they offer a comprehensive framework for decision-making. Whether they will also contribute to improvements in patient outlook remains to be proven
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
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