31 research outputs found

    Use of an experimental design model to determine the impact of different fermentation parameters on the development of flavour compounds in wine

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    An experimental design developed by YOUDEN and STEINER (1975) was successfully applied to micro-fermentation experiments with two different grape musts. This tool allowed the verification of the impact of several fermentation parameters on the fermentation course and on flavour development with a restricted number of experiments. The positive effects of a higher fermentation temperature on the development of 3-mercaptohexanol, an important contributor to the characteristic aroma of the Petite Arvine wine, could be demonstrated.

    Exterior-Interior Duality for Discrete Graphs

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    The Exterior-Interior duality expresses a deep connection between the Laplace spectrum in bounded and connected domains in R2\mathbb{R}^2, and the scattering matrices in the exterior of the domains. Here, this link is extended to the study of the spectrum of the discrete Laplacian on finite graphs. For this purpose, two methods are devised for associating scattering matrices to the graphs. The Exterior -Interior duality is derived for both methods.Comment: 15 pages 1 figur

    Accounting for risk of non linear portfolios: a novel Fourier approach

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    The presence of non linear instruments is responsible for the emergence of non Gaussian features in the price changes distribution of realistic portfolios, even for Normally distributed risk factors. This is especially true for the benchmark Delta Gamma Normal model, which in general exhibits exponentially damped power law tails. We show how the knowledge of the model characteristic function leads to Fourier representations for two standard risk measures, the Value at Risk and the Expected Shortfall, and for their sensitivities with respect to the model parameters. We detail the numerical implementation of our formulae and we emphasizes the reliability and efficiency of our results in comparison with Monte Carlo simulation.Comment: 10 pages, 12 figures. Final version accepted for publication on Eur. Phys. J.

    Propagating wave correlations in complex systems

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    We describe a novel approach for computing wave correlation functions inside finite spatial domains driven by complex and statistical sources. By exploiting semiclassical approximations, we provide explicit algorithms to calculate the local mean of these correlation functions in terms of the underlying classical dynamics. By defining appropriate ensemble averages, we show that fluctuations about the mean can be characterised in terms of classical correlations. We give in particular an explicit expression relating fluctuations of diagonal contributions to those of the full wave correlation function. The methods have a wide range of applications both in quantum mechanics and for classical wave problems such as in vibro-acoustics and electromagnetism. We apply the methods here to simple quantum systems, so-called quantum maps, which model the behaviour of generic problems on Poincaré sections. Although low-dimensional, these models exhibit a chaotic classical limit and share common characteristics with wave propagation in complex structures

    Effect of fresh red blood cell transfusions on clinical outcomes in premature, very low-birth-weight infants: The ARIPI randomized trial

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    Context: Even though red blood cells (RBCs) are lifesaving in neonatal intensive care, transfusing older RBCs may result in higher rates of organ dysfunction, nosocomial infection, and length of hospital stay. Objective: To determine if RBCs stored for 7 days or less compared with usual standards decreased rates of major nosocomial infection and organ dysfunction in neonatal intensive care unit patients requiring at least 1 RBC transfusion. Design, Setting, and Participants: Double-blind, randomized controlled trial in 377 premature infants with birth weights less than 1250 g admitted to 6 Canadian tertiary neonatal intensive care units between May 2006 and June 2011. Intervention: Patients were randomly assigned to receive transfusion of RBCs stored 7 days or less (n=188) vs standard-issue RBCs in accordance with standard blood bank practice (n=189). Main Outcome Measures: The primary outcome was a composite measure of major neonatal morbidities, including necrotizing enterocolitis, retinopathy of prematurity, bronchopulmonary dysplasia, and intraventricular hemorrhage, as well as death. The primary outcome was measured within the entire period of neonatal intensive care unit stay up to 90 days after randomization. The rate of nosocomial infection was a secondary outcome. Results: The mean age of transfused blood was 5.1 (SD, 2.0) days in the fresh RBC group and 14.6 (SD, 8.3) days in the standard group. Among neonates in the fresh RBC group, 99 (52.7%) had the primary outcome compared with 100 (52.9%) in the standard RBC group (relative risk, 1.00; 95% CI, 0.82-1.21). The rate of clinically suspected infection in the fresh RBC group was 77.7% (n=146) compared with 77.2% (n=146) in the standard RBC group (relative risk, 1.01; 95% CI, 0.90-1.12), and the rate of positive cultures was 67.5% (n=127) in the fresh RBC group compared with 64.0% (n=121) in the standard RBC group (relative risk, 1.06; 95% CI, 0.91-1.22). Conclusion: In this trial, the use of fresh RBCs compared with standard blood bank practice did not improve outcomes in premature, very low-birth-weight infants requiring a transfusion. Trial Registration: clinicaltrials.gov Identifier: NCT00326924; Current Controlled Trials Identifier: ISRCTN65939658. ©2012 American Medical Association. All rights reserved

    Comparing very low birth weight versus very low gestation cohort methods for outcome analysis of high risk preterm infants

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    © 2017 The Author(s). Background: Compared to very low gestational age (<32 weeks, VLGA) cohorts, very low birth weight (<1500 g; VLBW) cohorts are more prone to selection bias toward small-for-gestational age (SGA) infants, which may impact upon the validity of data for benchmarking purposes. Method: Data from all VLGA or VLBW infants admitted in the 3 Networks between 2008 and 2011 were used. Two-thirds of each network cohort was randomly selected to develop prediction models for mortality and composite adverse outcome (CAO: mortality or cerebral injuries, chronic lung disease, severe retinopathy or necrotizing enterocolitis) and the remaining for internal validation. Areas under the ROC curves (AUC) of the models were compared. Results: VLBW cohort (24,335 infants) had twice more SGA infants (20.4% vs. 9.3%) than the VLGA cohort (29,180 infants) and had a higher rate of CAO (36.5% vs. 32.6%). The two models had equal prediction power for mortality and CAO (AUC 0.83), and similarly for all other cross-cohort validations (AUC 0.81-0.85). Neither model performed well for the extremes of birth weight for gestation (<1500 g and ≥32 weeks, AUC 0.50-0.65; ≥1500 g and <32 weeks, AUC 0.60-0.62). Conclusion: There was no difference in prediction power for adverse outcome between cohorting VLGA or VLBW despite substantial bias in SGA population. Either cohorting practises are suitable for international benchmarking

    Private-Equity für den Mittelstand – Attraktivitätsfaktoren für die Investoren bei der Partnerschaft auf Zeit mit Fokus auf die Expansion in den Osten

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    Der Markt für das private Beteiligungskapital Private Equity (PE) hat in den letzten Jahren trotz Krisen signifikant an Bedeutung gewonnen. Unbekannt war bisher, ob agierende Investoren die Entscheidungsfaktoren in diesem Zusammenhang regional signifikant unterschiedlich gewichten. Die vorliegende Arbeit ging von der Annahme aus, dass es solche regionale Differenzierungen der Marktteilnehmer geben müsse. Der Forschungsschwerpunkt ist ein regionaler Vergleich von ausgewählten Faktoren, welche mittels schriftlicher Umfrageergebnisse von 88 Investoren verglichen wurden. Hierbei wurden die Regionen Westeuropa (WE), Zentral- und Osteuropa (CEE) und die Gemeinschaft unabhängiger Staaten (CIS) betrachtet. Diese Untersuchung untermauert, dass PE-Markteilnehmer nur einige wenige Faktoren abhängig von der Region identifizieren. Abgesehen davon konnte nachgewiesen werden, dass CEE und CIS im Vergleich zu entwickelten Regionen wie WE attraktivere Investmentregionen für PE darstellen, wobei die Indikatoren der Attraktivität regional unterschiedlich gewichtet werden
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