29 research outputs found
Quasi-Monte Carlo methods for Markov chains with continuous multi-dimensional state space
No full textWe describe a quasi-Monte Carlo method for the simulation of discrete time Markov chains with continuous multi-dimensional state space. The method simulates copies of the chain in parallel. At each step the copies are reordered according to their successive coordinates. We prove the convergence of the method when the number of copies increases. We illustrate the method with numerical examples where the simulation accuracy is improved by large factors compared with Monte Carlo simulation. © 2010 IMACS.Beauwens R, 1998, MATH COMPUT SIMULAT, V47, P83; Dimov I, 2001, MATH COMPUT SIMULAT, V55, P1, DOI 10.1016-S0378-4754(00)00257-3; El Haddad R, 2008, MONTE CARLO AND QUASI-MONTE CARLO METHODS 2006, P413; Entacher K, 2003, MATH COMPUT SIMULAT, V62, P217, DOI 10.1016-S0378-4754(02)00219-7; JOHNSON H, 1987, J FINANC QUANT ANAL, V22, P277, DOI 10.2307-2330963; L'Ecuyer P, 2006, MONTE CARLO AND QUASI-MONTE CARLO METHODS 2004, P331, DOI 10.1007-3-540-31186-6_19; Lecot C, 2004, MONTE CARLO AND QUASI-MONTE CARLO METHODS 2002, P329; LECOT C, 1989, COMPUTING, V41, P41, DOI 10.1007-BF02238728; Lecot C., 2004, Monte Carlo Methods and Applications, V10, DOI 10.1515-mcma.2004.10.3-4.377; L'Ecuyer P, 1999, OPER RES, V47, P159, DOI 10.1287-opre.47.1.159; L'Ecuyer P, 2008, OPER RES, V56, P958, DOI 10.1287-opre.1080.0556; NIEDERREITER H., 1992, RANDOM NUMBER GENERA; SABELFELD KK, 2004, MONTE CARLO METH, V10, P1830
A note about reproducibility in visual ITC
No full textWe present several orders of magnitude of some anomaly occurring rates f that we obtained in visual instrumental transcommunication. We used two techniques, the first one is numeric and relies on Perlin noise, it was run by the second author who presents solid mediumship and obtained f ~ 10^(-3). The second one is a reproduction of a mist technique developed by the Institut français de recherche et d'expérimentation spirite (Ifres), it was run by the first author who has no mediumistic ability and obtained f ~ 10^(-5)
Polymerase-chain-reaction-based semi-quantification of hepatitis D viraemia in patients treated with high doses of alpha 2b interferon
No full textTo study the antiviral efficacy of high doses of alpha 2b interferon (alpha 2b-IFN) for chronic hepatitis D treatment, we used polymerase-chain-reaction(PCR)-based semi-quantitative detection of HDV RNA. The semi-quantification method used was based on the appearance of a positive amplification signal as a function of the number of PCR cycles. By amplifying dilutions (10(-1)-10(-8)) of an HDV-positive woodchuck liver RNA, we confirmed that exponential amplification efficacy occurred at between 20 and 30 cycles. Positive signals were observed from dilution 10(-2) (gel electrophoresis after 20 cycles of PCR) to dilution 10(-7) (hybridization after 30 cycles of PCR). To characterize the HDV RNA level in sera of 8 patients treated with alpha 2b-IFN (10 MU/3 times a week) for 1 year, we extracted RNA from serum samples taken every 6 months. All samples were amplified in parallel for 20 and 30 PCR cycles. Analysis of HDV cDNA after ethidium bromide/agarose gel electrophoresis and after molecular hybridization (100 times more sensitive than gel analysis), enabled us to grade the signals observed from negative to positive as 1+, 2+, 3+ and 4+, with all results being positive. Three types of evolution of HDV viraemia were evidenced among the 8 treated patients. HDV replication continued to occur at a high level at the 6th and 12th month in 2 patient sera. For 2 other patients, an HDV RNA decrease or disappearance was evidenced in the serum at the 6th month; however, viral replication recurred at a higher level at the 12th month.(ABSTRACT TRUNCATED AT 250 WORDS
A quasi-Monte Carlo method for the coagulation equation
No full textInternational audienceWe propose a quasi-Monte Carlo algorithm for the simulation of the continuous coagulation equation. The mass distribution is approximated by a finite number of numerical particles. Time is discretized and quasi-random points are used at every time step to determine whether each particle is undergoing a coagulation. Convergence of the scheme is proved when goes to infinity, if the particles are relabeled according to their increasing mass at each time step. Numerical tests show that the computed solutions are in good agreement with analytical ones, when available. Moreover, the error of the QMC algorithm is smaller than the error given by a standard Monte Carlo scheme using the same time step and number of numerical particles
Long-term Results of Totally Laparoscopic Aortobifemoral Bypass
No full textOBJECTIVES: The aim was to estimate the long-term results and patency rates of totally laparoscopic aortobifemoral bypass in aorto-iliac occlusive disease (AIOD). METHODS: All 87 patients who received a laparoscopic aortobifemoral bypass for AIOD on an intention to treat basis between October 2003 and October 2013 were identified. All operations were performed by the same surgical team using a totally laparoscopic technique. Demographic, pre-operative, peri-operative, and follow up variables were collected and analyzed. Patients were followed up at 1 month post-operatively and annually thereafter. Patency rates were calculated in accordance with published patency reporting standards. RESULTS: The median age was 57 years (range 40-78 years). The conversion rate was 20.6% overall. The thirty-day post-operative mortality was 1.1%. Six patients required early re-intervention. There were no graft infections. The median length hospital stay was 6 days (range 4-39 days). The mean follow up was 58.0 months (range 1-133 months). Graft limb based primary, primary assisted, and secondary patency rates were respectively 96.1%, 98.1% and 99.4% at 1 year, and 83.0%, 92.0% and 97.0% at 5 years. CONCLUSION: Totally laparoscopic aortobifemoral bypass is a safe alternative to open surgery in selected patients, with excellent long-term patency rates, albeit at the cost of a steep learning curve.status: Publishe
Adenosine 3\u27:5\u27-monophosphate and quanosine 3\u27:5\u27-monophosphate. Levels and cyclase activities in liver and adipose tissue from diabetic mice (db/db).
No full textBiorefinery of rice husk to obtain functionalized bioactive compounds
No full textThe biomass industrialization valorisation of grains and cereals is considered an opportunity for the countries where agro-industrial activity is one of its main economic activities, rendering new higher-value products with a concomitant solution to waste accumulation issues. To that end, in this work we describe and characterise bioactive compounds generation from rice husk by semisolid fermentation, obtained from 500 g of the material at room temperature and 60% humidity with mixed cultures of Phanerochaete chrysosporium and Gloeophyllum trabeum. The extract was evaluated in different situations: murine mammary tumour cells (4T1), normal cells (NIH 3T3) and in Lactobacillus acidophilus, and Trichoderma harzianum. The results exhibited that the extract inhibited 4T1 cells at concentrations higher than 20μg/mL, but did not inhibit normal cells, and displayed germicide activity after 3 days incubations. We propose that these functionalized compounds have a potential application in industry/agriculture/medicine obtained from rice husk waste
A quasi-Monte Carlo method for the coagulation equation
No full textInternational audienceWe propose a quasi-Monte Carlo algorithm for the simulation of the continuous coagulation equation. The mass distribution is approximated by a finite number of numerical particles. Time is discretized and quasi-random points are used at every time step to determine whether each particle is undergoing a coagulation. Convergence of the scheme is proved when goes to infinity, if the particles are relabeled according to their increasing mass at each time step. Numerical tests show that the computed solutions are in good agreement with analytical ones, when available. Moreover, the error of the QMC algorithm is smaller than the error given by a standard Monte Carlo scheme using the same time step and number of numerical particles
Intégration de l’analyse moléculaire dans la prise en charge des patients présentant un adénocarcinome pulmonaire pour une utilisation optimale des thérapies ciblées
No full textErratum to “Practice variation in anastomotic leak after esophagectomy: Unravelling differences in failure to rescue” [Eur J Surg Oncol 49 (5) (May 2023) 974–982](S074879832300032X)(10.1016/j.ejso.2023.01.010)
No full textThe publisher regrets that when the article was published the following collaboration authors from the “TENTACLE – Esophagus collaborative group” appeared incorrectly in the main author list due to a technical error: Writing Committee, Joos Heisterkamp, Fatih Polat, Jeroen Schouten, Pritam Singh, Study collaborators. This has now been corrected. The publisher would like to apologise for any inconvenience caused
