Search results for " Opera"
showing 10 items of 3606 documents
Phase Equilibria Involved in Extractive Distillation of Dipropyl Ether + 1-Propyl Alcohol Using N,N-Dimethylformamide as Entrainer
2007
Consistent vapor−liquid equilibrium data for the binary and ternary systems dipropyl ether (1) + 1-propyl alcohol (2) + N,N-dimethylformamide (3) are reported at 101.3 kPa. The results indicate that dipropyl ether (1) + N,N-dimethylformamide (3) system exhibits a positive deviation from ideal behavior and that 1-propyl alcohol (2) + N,N-dimethylformamide (3) system deviates negatively from ideality. The activity coefficients of the solutions were correlated by the Wilson, NRTL, and UNIQUAC models. It is shown that these models allow a very good prediction of the phase equilibrium of the ternary system using the pertinent parameters of the binary systems. In addition, the Wisniak−Tamir relat…
Contingent claim valuation in a market with different interest rates
1995
The problem of contingent claim valuation in a market with a higher interest rate for borrowing than for lending is discussed. We give results which cover especially the European call and put options. The method used is based on transforming the problem to suitable auxiliary markets with only one interest rate for borrowing and lending and is adapted from a paper of Cvitanic and Karatzas (1992) where the authors study constrained portfolio problems.
Value preserving portfolio strategies and the minimal martingale measure
1998
We consider some relations between the minimal martingale measure and the value preserving martingale measure in a continuous-time securities market. Under the assumption of continuous share prices we show that under a structure condition both these martingale measures exist and indeed coincide. This however does not mean that the corresponding concepts of value preserving portfolio strategies and (local) risk minimisation in the area of option hedging in incomplete markets are identical.
Adaptive memory programing for the robust capacitated international sourcing problem
2008
The International Sourcing Problem consists of selecting a subset from an available set of potential suppliers internationally located. The selected suppliers must meet the demand for items from a set of plants, which are also located worldwide. Since the costs are affected by macroeconomic conditions in the countries where the supplier and the plant are located, the formulation considers the uncertainty associated with changes in these conditions. We formulate the robust capacitated international sourcing problem by means of a scenario-optimization approach. When dealing with uncertainty, one of the most common approaches in the literature is to formulate the problem via a set of possible …
Prediction of stock index futures prices based on fuzzy sets and multivariate fuzzy time series
2015
Abstract This paper makes a prediction of Chinese stock index (CSI) future prices using fuzzy sets and multivariate fuzzy time series method. We select Chinese CSI 300 index futures as the research object. The fuzzy time series model combines the fuzzy theory and the time series theory, thus this model can solve the fuzzy data in stock index futures prices. This paper establishes a multivariate model and improves the accuracy of computation. By combing traditional fuzzy time series models and rough set method, we use fuzzy c-mean algorithm to make the data into discrete. Further more, we deal with the rules in mature modules of the rough set and then refine the rules using data mining algor…
Comparison between a guaiac and three immunochemical faecal occult blood tests in screening for colorectal cancer
2012
Abstract Background The aim of this study was to compare the performance of the guaiac-based faecal occult blood test (G-FOBT), with that of three immunochemical faecal occult blood tests (I-FOBT) which allow automatic interpretation. Patients and methods Under the French organised screening programme, 85,149 average-risk individuals aged 50–74 participating in the third screening round, performed both the G-FOBT (Hemoccult-II test) and one of the I-FOBTs: FOB-Gold, Magstream and OC-Sensor. Results Given the chosen threshold, the positivity ratio between the different I-FOBTs and the G-FOBT was 2.4 for FOB-Gold, 2.0 for Magstream and 2.2 for OC-Sensor (P = 0.17). The three I-FOBTs were supe…
Immunochemical faecal occult blood tests are superior to guaiac-based tests for the detection of colorectal neoplasms
2008
The aim of this study was to compare the performance of a guaiac-based faecal occult blood test (G-FOBT) with that of an immunochemical faecal occult blood test (I-FOBT). A total of 17,215 average risk individuals aged 50 to 74 enrolled in a population-based organised screening programme and performed a 3-day G-FOBT and a 2-day I-FOBT simultaneously. Among participants, 3.1% were found positive for the G-FOBT and 6.9% for the I-FOBT (p<10(-4)). Among the 1205 participants who tested positive and underwent a colonoscopy, the number of detected cancers and advanced adenomas was respectively 2.6 times higher and 3.5 times higher with the I-FOBT than with the G-FOBT. The positive predictive val…
AMH MEASUREMENT VERSUS OVARIAN ULTRASOUND IN THE DIAGNOSIS OF POLYCYSTIC OVARY SYNDROME IN DIFFERENT PHENOTYPES.
2015
This study was designed to assess the value of serum anti-Müllerian hormone (AMH) in the diagnosis of polycystic ovary syndrome (PCOS) in various phenotypes and to assess ovarian ultrasound parameters.We performed a retrospective matched controlled study of 113 females with various PCOS phenotypes and 47 matched controls. The diagnostic utility of AMH measurement and ovarian ultrasound were compared. Using receiver operating characteristic (ROC) curve analyses, the threshold for AMH (4.7 ng/mL) and ultrasound parameters (follicle number per ovary [FNPO]22 and ovarian volume [OV]8 cc) were established.In the entire cohort, AMH had a low sensitivity of 79%; while FNPO and OV were 93% and 68%,…
The Association between Peripheral Blood Cells and the Frailty Syndrome in Patients with Cardiovascular Diseases
2020
Background: Frailty syndrome is characterized by multisystem dysregulation frequently found in older individuals or even in younger patients with chronic disabling diseases such as cardiovascular diseases. Objective: To determine whether peripheral blood cell count, and its subpopulations, red blood cell and platelets, morphology and different ratios (neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio and red blood distribution width-to-platelet ratio) are associated with cardiac frail patients, and through this to improve the prediction of frailty status in patients with cardiovascular diseases. Methods: An observational, retrospective, cohort study enrolling 179 patients with c…
Lack of prompt expansion of cytomegalovirus pp65 and IE-1-specific IFNγ CD8+ and CD4+ T cells is associated with rising levels of pp65 antigenemia an…
2009
Rising levels of cytomegalovirus (CMV) DNAemia and/or pp65 antigenemia have been observed during pre-emptive ganciclovir therapy in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-SCT). We assessed the incidence of this event in our series, and investigated whether its occurrence was associated with an impairment in the CMV-specific T-cell response. A total of 36 allo-SCT recipients experienced one or more episodes of active CMV infection (n=68) that were pre-emptively treated with val(ganciclovir). Rising levels of antigenemia and DNAemia, and an isolated increase in antigenemia, were observed in 39.7 and 2.9% of all episodes, respectively. Receipt of corticost…