Search results for "Opera"
showing 10 items of 8665 documents
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…
The Small Size and Superficial Location Suggest That Laparoscopic Partial Nephrectomy Is the First Choice for the Treatment of Juxtaglomerular Cell T…
2021
BackgroundJuxtaglomerular cell tumor (JGCT) is a very rare disease, and surgical resection is the only possible way to cure this tumor. Open nephrectomy and partial nephrectomy have been reported to manage JGCTs with excellent results in the previous reviews. Laparoscopic surgery has been popularized in recent years, while critical issues associated with laparoscopic surgical management have been seldom reported. We summarized the JGCTs in our center to discover the optimal surgical management and its anatomic foundation.MethodsIn this retrospective study, we enrolled a total of 14 JGCT patients. All patients received surgeries and were followed up for up to 11 years. We mainly summarized t…
[Transphenoidal endoscopic approaches for pituitary adenomas: a critical review of our experience].
2010
Abstract Background The surgical approach to the pituitary fossae has evolved from transcranial to sublabial and transseptal microscopic ones, up to the current transsphenoidal endoscopic approach. Objectives To present our experience in the transnasal transsphenoidal approach for pituitary adenomas and the modifications introduced to improve tumoral resection and to lower iatrogenia. Material and methods Over nine years, we operated on 37 patients with pituitary adenomas using the transsphenoidal endoscopic approach. We utilised optical lens of 0° (approach) and 30° (adenoma resection), optic navigator, surgical instruments for nasal endoscopic and pituitary surgery. During the neurosurgic…
Continent Anal Urinary Diversion in Classic Bladder Exstrophy: 45-Year Experience
2017
Objective To evaluate the long-term outcomes in patients with classic bladder exstrophy and continent anal urinary diversion (CAD) for continence, upper urinary tract status, secondary malignancies, and sexual function. Patients and Methods The medical records of 82 exstrophy patients having undergone CAD in our department between 1970 and 2015 were reviewed. Patients were invited for follow-up examinations and asked to complete validated questionnaires relating to sexual function. Results Thirty-two of 57 eligible patients with a median follow-up of 23.9 years were included in the study. Ninety-seven percent of patients were fully continent during daytime. Upper urinary tract and renal fun…
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…
Standardized long-term follow-up after endoscopic resection of large, nonpedunculated colorectal lesions: a prospective two-center study.
2014
Endoscopic removal of large, nonpedunculated colorectal lesions is challenging. Long-term outcome data based on standardized protocols, including detailed inspection of the resection site, are scarce. The aims of the present study were to evaluate the safety and efficacy of endoscopic resection (ER) of large, nonpedunculated lesions (LNLs;20 mm) and to assess the long-term recurrence rate afterward.A total of 243 consecutive patients (141 men, 102 women) with 252 adenomas (20 mm) was followed up using a standardized protocol after complete ER. After endoscopic treatment, the patients received standardized follow-up examinations after 3-6 months and 12 months. The postpolypectomy scar was re…