PREMIUM, a benchmark on the quantification of the uncertainty of the physical models in the system thermal-hydraulic codes: methodologies and data review

The objective of the Post-BEMUSE Reflood Model Input Uncertainty Methods (PREMIUM) benchmark is to progress on the issue of the quantification of the uncertainty of the physical models in system thermalhydraulic codes by considering a concrete case: the physical models involved in the prediction of core reflooding. The present document was initially conceived as a final report for the Phase I “Introduction and Methodology Review” of the PREMIUM benchmark. The objective of Phase I is to refine the definition of the benchmark and publish the available methodologies of model input uncertainty quantification relevant to the objectives of the benchmark. In this initial version the document was approved by WGAMA and has shown its usefulness during the subsequent phases of the project. Once Phase IV was completed, and following the suggestion of WGAMA members, the document was updated adding a few new sections, particularly the description of four new methodologies that were developed during this activity. Such developments were performed by some participants while contributing to PREMIUM progress (which is why this report arrives after those of other phases). After this revision the document title was changed to “PREMIUM methodologies and data review”. The introduction includes first a chapter devoted to contextualization of the benchmark in nuclear safety research and licensing, followed by a description of the PREMIUM objectives. Next, a description of the Phases in which the benchmark is divided and its organization is explained. Chapter two consists of a review of the involvement of the different participants, making a brief explanation of the input uncertainty quantification methodologies used in the activity. The document ends with some conclusions on the development of Phase I, some more general remarks and some statements on the benefits of the benchmark, which can be briefly summarized as it follows: - Contribution to development of tools and experience related to uncertainty calculation and promotion of the use of BEPU approaches for licensing and safety assessment purposes; - Contribution to prioritization of improvements to thermal-hydraulic system codes; - Contribution to a fluent and close interaction between the scientific community and regulatory organizations. Appendices include the complete description of the experimental data FEBA/SEFLEX used in the benchmark and the methodologies CIRCÉ and FFTBM and the general requirements and description specification used for Phase I. Due to the revision of the document, four extra appendixes have been added related to the methods developed during the activity, MCDA DIPE, Tractebel IUQ and PSI methods

How to define a Minimal Clinically Individual state (MCIS) with pain VAS in daily practice for patients suffering from musculoskeletal disorders

<p><b>OBJECTIVES:</b> Pain is frequently the primary variable in symptomatic clinical trials for the evaluation of rheumatological disorders. The protocol of such trials mention a minimum level of pain as an entry criterion [e.g. a level above the Patient Acceptable Symptoms State (PASS)] and the changes in pain as the primary variable. Usually, the results are expressed at a group level as the mean changes in pain. However, the presentation at an individual level and, in particular, the percentage of patients with a Low Disease Activity State at the end of the study seems more clinically relevant. Pain is usually evaluated using a continuous variable such as a 0-100 visual analogue scale. The cut-offs permitting one to define both the entry criterion and the LDAS are not well established. The objective of this study was to evaluate such cut-offs using a patient-derived perspective.</p> <p><b>METHODS:</b> Study design: cross-sectional study. Patients: consecutive out patients suffering from chronic rheumatic diseases familiar with the use of a VAS to evaluate their level of pain. Data collected: two questions were asked the patients at the end of the visit: "Based on the experience you have because of your chronic rheumatic disorder, could you please specify the level of pain below which you consider your disease as inactive ? Moreover, could you please also specify the level of pain above which you consider taking a pain killer?" Before answering the second question, it was explained to the patient that their answer to the second question could be similar to their response to the first one. For the two questions, the cumulative percentage of patients (disease inactive and pain killer intake) were calculated for each level of pain.</p> <p><b>RESULTS:</b> The underlying disease of the 137 evaluated patients (mean age: 57+/-16 and female sex: 76%) was rheumatoid arthritis (n = 59), ankylosing spondylitis (n = 19), SLE (n = 2), back pain (n = 20), or peripheral osteoarthritis (n = 37). The mean disease duration was 12+/-10 years. At the time of the study, the current level of pain evaluated on a 0-100 VAS was 33+/-22. The LDAS was 49, 36 and 25 for our patient population at the 25th, 50th and 75th percentiles, respectively. The pain killer intake level was 32, 48, 64 at the 25th, 50th, 75th percentile respectively.</p> <p><b>CONCLUSION:</b> This study suggests that LDAS and PASS may be distinct concepts. The methodological approach adopted here could be of interest for specifying the minimum level of symptoms at entry in a symptomatic trial (PASS) and also to present results in terms of the percentage of patients in good condition (LDAS) at the end of a trial.</p&gt

Care related pain and functional restoration for chronic low back pain: A prospective study

AbstractObjectiveTo assess care related pain during a program of functional restoration for chronic low back pain.Patients and methodsChronic low back pain patients were prospectively included in a program of functional restoration. Low back pain was recorded before and after each morning and afternoon sessions, all over the program of functional restoration, for equivalence study. Equivalence was admitted if 95% confidence interval of the difference in pain falled wholly in the interval ±10/100mm. Medication was recorded during the program. Progression of the patients during the program and 3-month effectiveness were also recorded for internal validity.ResultsThirty-seven patients were included. They underwent a progression in load and spent energy during the program. Follow-up also indicated improvement of functional ability and quality of life. There was no variation in pain during the program however medication intake increased.ConclusionThere was no significant care related pain during our program of functional restauration for chronic low back pain. This may be due to adaptation of the medication and suggests the importance of close medical management of patients during functional restoration