Multimodal Excitation to Model the Quasibiennial Oscillation.

The quasibiennial oscillation (QBO) of stratospheric winds is the most striking example of mean-flow generation and reversal by the nonlinear interactions of internal waves. Previous studies have used an idealized monochromatic forcing to investigate the QBO. Here we instead force a more realistic continuous wave spectrum. Unexpectedly, spreading the wave energy across a wide frequency range leads to more regular oscillations. We also find that different forcing spectra can yield the same QBO. Multimodal wave forcing is thus essential for understanding wave-mean-flow interactions in nature.

SimPhy: a simulation game to lessen the impact of phytosanitaries on health and the environment--the case of Merja Zerga in Morocco.

Diffuse phytosanitary pollution is a complex phenomenon to manage. Reducing this type of pollution is one of today's key socio-economic and environmental challenges. At the regional level, few approaches enable the actors concerned to implement agricultural management strategies to reduce the use and impact of phytosanitary products. Our research problem focused on the consequences of intensive agriculture and, in particular, how to evaluate the impact of phytosanitary products on human health and the environment. In this article, we present the SimPhy simulation game which places the actors from a given region directly into a situation in which they manage farms whilst under pressure to reduce phytosanitaries (quantity and toxicity). The application focused on the Merja Zerga catchment area in Morocco. The region is dominated by intensive agriculture which is located upstream from a Ramsar-classified wetland area. The SimPhy simulation game is based on a decision support system-type tool. It allows us to anticipate the impact of regulations on farming systems. It also enables us to analyse the consequences of the actors' strategies on farm economies, human health and the quality of ecosystems. Initial results from the SimPhy simulation game enabled the technicians from Agricultural Development Center (CDA) themselves to learn about managing agricultural production systems in a dynamic and interactive fashion. With the simulation game, it was possible to learn about the farmer's ability to adapt to new regulatory constraints, and the involved consequences for toxicity risks for human health and the environment.

An impact-driven dynamo for the early Moon.

The origin of lunar magnetic anomalies remains unresolved after their discovery more than four decades ago. A commonly invoked hypothesis is that the Moon might once have possessed a thermally driven core dynamo, but this theory is problematical given the small size of the core and the required surface magnetic field strengths. An alternative hypothesis is that impact events might have amplified ambient fields near the antipodes of the largest basins, but many magnetic anomalies exist that are not associated with basin antipodes. Here we propose a new model for magnetic field generation, in which dynamo action comes from impact-induced changes in the Moon's rotation rate. Basin-forming impact events are energetic enough to have unlocked the Moon from synchronous rotation, and we demonstrate that the subsequent large-scale fluid flows in the core, excited by the tidal distortion of the core-mantle boundary, could have powered a lunar dynamo. Predicted surface magnetic field strengths are on the order of several microteslas, consistent with palaeomagnetic measurements, and the duration of these fields is sufficient to explain the central magnetic anomalies associated with several large impact basins.

Experimental determination of zonal winds driven by tides.

We describe a new phenomenon of zonal wind generation by tidal forcing. Following a recent theoretical and numerical analysis [A. Tilgner, Phys. Rev. Lett. 99, 194501 (2007)], we present the first experimental evidence that the nonlinear self-interaction of a tidally forced inertial mode can drive an intense axisymmetric flow in a rotating deformed sphere. Systematic measurements of zonal flows are carried out by an embarked system of particle image velocimetry, allowing the determination of general scaling laws. These results are fully relevant for zonal winds generation in planets and stars, and illustrate a generic mechanism of geostrophic flow generation by periodic forcing.

Evaluation of disease activity assessments in patients with rheumatoid arthritis and an inadequate response to anti-TNF therapy: analyses of abatacept clinical trial data.

OBJECTIVES: To assess the ability of efficacy measures that incorporate onset or sustainability to detect treatment effect or reflect patient satisfaction, using exploratory analyses of data from the ATTAIN (Abatacept Trial in Treatment of Anti-TNF INadequate Responders) trial. METHODS: 218 abatacept- and 99 placebo-treated patients were evaluated. Reporting methods included time to onset (first American College of Rheumatology [ACR] 50 response/Low Disease Activity State [LDAS; DAS28 < or =3.2]) and sustainability of ACR50/LDAS, both assessed according to discriminatory capacity (number of patients needed to study [NNS]) and patient satisfaction with treatment. RESULTS: Efficacy measures incorporating elements of sustainability or onset decreased discriminatory capacity, while sustainability, but not onset of action, was important in reflecting patient satisfaction. CONCLUSIONS: Optimal assessment methods depend on whether the outcome of interest is ability to detect treatment effects or to reflect patient satisfaction. Sustainability of response (and possibly, at a lower magnitude, fast onset of action) may be important when evaluating patient satisfaction with RA therapies in patients who have previously failed anti-TNF therapy.

Clinical and ultrasonographic predictors of joint replacement for knee osteoarthritis: results from a large, 3-year, prospective EULAR study.

OBJECTIVES: To determine clinical and ultrasonographic predictors of joint replacement surgery across Europe in primary osteoarthritis (OA) of the knee. METHODS: This was a 3-year prospective study of a painful OA knee cohort (from a EULAR-sponsored, multicentre study). All subjects had clinical evaluation, radiographs and ultrasonography (US) at study entry. The rate of knee replacement surgery over the 3-year follow-up period was determined using Kaplan-Meier survival data analyses. Predictive factors for joint replacement were identified by univariate log-rank test then multivariate analysis using a Cox proportional-hazards regression model. Potential baseline predictors included demographic, clinical, radiographic and US features. RESULTS: Of the 600 original patients, 531 (88.5%), mean age 67+/-10 years, mean disease duration 6.1+/-6.9 years, had follow-up data and were analysed. During follow-up (median 3 years; range 0-4 years), knee replacement was done or required for 94 patients (estimated event rate of 17.7%). In the multivariate analysis, predictors of joint replacement were as follows: Kellgren and Lawrence radiographic grade (grade > or =III vs or =4 mm vs <4 mm) (HR = 2.63 (95% CI 1.70 to 4.06), p<0.0001); knee pain intensity on a 0-100 mm visual analogue scale (> or =60 vs <60) (HR = 1.81 (95% CI 1.15 to 2.83), p=0.01) and disease duration (> or =5 years vs <5 years) (HR=1.63 (95% CI 1.08 to 2.47), p=0.02). Clinically detected effusion and US synovitis were not associated with joint replacement in the univariate analysis. CONCLUSION: Longitudinal evaluation of this OA cohort demonstrated significant progression to joint replacement. In addition to severity of radiographic damage and pain, US-detected effusion was a predictor of subsequent joint replacement.

Sedimentation of particles in a vigorously convecting fluid.

The sedimentation of particles in a vigorously convecting fluid is a process of great interest in various geophysical and industrial settings. Using a classical Rayleigh-Bénard setup with salty water as a working fluid and PMMA particles, we systematically quantify the progressive settling of a large number of heavy particles initially distributed homogeneously through the tank. Our two control parameters are the Rayleigh number Ra characterizing the vigor of convection and the density ratio between the particles and the fluid Deltarho/rho. In all our experiments, the time evolution of the solid fraction of suspended particles is correctly described by a diffusion-convection equation, taking into account a constant settling velocity given by the classical Stoke's law with an apparent viscosity due to small-scale turbulent motions, as well as a time-independent diffusive flux of particles from the bottom of the tank. We define scaling laws for this diffusive flux as well as for the equilibrium value of the suspended particles solid fraction as a function of Ra and Deltarho/rho, in agreement with the experimental results.

Evaluation of different methods used to assess disease activity in rheumatoid arthritis: analyses of abatacept clinical trial data.

OBJECTIVES: To evaluate different methods of reporting response to treatment or disease status for their ability to discriminate between active therapy and placebo, or to reflect structural progression or patient satisfaction with treatment using an exploratory analysis of the Abatacept in Inadequate Responders to Methotrexate (AIM) trial. METHODS: 424 active (abatacept approximately 10 mg/kg) and 214 placebo-treated patients with rheumatoid arthritis (RA) were evaluated. METHOD: of reporting included: (1) response (American College of Rheumatology (ACR) criteria) versus state (disease activity score in 28 joints (DAS28) criteria); (2) stringency (ACR20 vs 50 vs 70; moderate disease activity state (MDAS; DAS28 <5.1) vs low disease activity state (LDAS; DAS28 or=2). More stringent criteria (at least ACR50/LDAS), faster onset (3 visits) of ACR50/LDAS best reflected patient satisfaction (positive LR >10). CONCLUSIONS: The optimal method for reporting a measure of disease activity may differ depending on the outcome of interest. Time to onset and sustainability can be important factors when evaluating treatment response and disease status in patients with RA.

The 6-month safety and efficacy of abatacept in patients with rheumatoid arthritis who underwent a washout after anti-tumour necrosis factor therapy or were directly switched to abatacept: the ARRIVE trial.

OBJECTIVE: To assess the safety, tolerability and efficacy of abatacept in patients with rheumatoid arthritis (RA) who had failed anti-tumour necrosis factor (TNF) therapy and were switched to abatacept directly or after completing washout. METHODS: In this international, 6-month, open-label trial, patients had active RA, an inadequate response to anti-TNF therapy for 3 months or longer and a disease activity score in 28 joints (DAS28 (C-reactive protein; CRP) of 5.1 or greater. "Washout" patients discontinued anti-TNF therapy 2 months or longer pre-screening; "direct-switch" patients began abatacept ( approximately 10 mg/kg) at their next scheduled anti-TNF therapy dose. RESULTS: 1046 patients were treated (449 washout, 597 direct-switch; baseline characteristics were similar between groups). At 6 months, adverse events (AE; 78.0% vs 79.2%), serious AE (11.1% vs 9.9%) and discontinuations due to AE (3.8% vs 4.0%) and serious AE (2.0% vs 1.3%) were comparable in washout versus direct-switch patients. There were no opportunistic infections. At 6 months, in washout versus direct-switch patients, similar clinically meaningful improvements were seen in DAS28 (CRP) (> or =1.2 unit improvement, 59.5% vs 53.6%, respectively; low disease activity state, 22.5% vs 22.3%; DAS28-defined remission, 12.0% vs 13.7%), physical function (health assessment questionnaire disability index > or =0.22 improvement; 46.3% vs 47.1%) and health-related quality of life (mean change in short-form 36 scores: physical component summary, 5.5 vs 6.1; mental component summary, 4.8 vs 5.4). CONCLUSION: Abatacept demonstrated acceptable safety and tolerability and clinically meaningful efficacy over 6 months in patients with inadequate response to anti-TNF therapy. Results were comparable with or without a washout, supporting direct switching from anti-TNF therapy to abatacept as an option in clinical practice. TRIAL REGISTRATION NUMBER: NCT00124982.

Efficacy and safety of the selective co-stimulation modulator abatacept following 2 years of treatment in patients with rheumatoid arthritis and an inadequate response to anti-tumour necrosis factor therapy.

OBJECTIVE: To evaluate the safety and efficacy of abatacept during 2 years of the ATTAIN (Abatacept Trial in Treatment of Anti-TNF INadequate responders) trial in patients with rheumatoid arthritis. METHODS: Patients completing the 6-month, double-blind period were eligible to enter the long-term extension; patients received abatacept approximately 10 mg/kg, plus disease-modifying antirheumatic drugs. Safety and efficacy (American College of Rheumatology (ACR) criteria responses, DAS28 (C-reactive protein), HAQ-DI, SF-36, Medical Outcomes Study Sleep Problems Index, fatigue VAS) were assessed through 2 years. RESULTS: 317 patients (218 from the abatacept and 99 from the placebo group) entered and 222 (70%) completed 18 months of long-term extension treatment. The incidence and type of adverse events were consistent between the double-blind and cumulative (double-blind plus long-term extension) periods. Rates of serious adverse events were 25.6 and 23.4 per 100 patient-years in the double-blind versus cumulative period. At 6 months and 2 years, using non-responder analyses, ACR responses in abatacept-treated patients were: ACR 20, 59.4% and 56.2%; ACR 50, 23.5% and 33.2%; ACR 70, 11.5% and 16.1%; HAQ-DI responses were 54.4% and 47.9%. At 6 months and 2 years, using post-hoc as-observed analyses, the percentage of patients (95% confidence interval) achieving DAS28 (C-reactive protein) low disease activity score (< or = 3.2) and DAS28 (C-reactive protein)-defined remission (< 2.6) increased from 18.3% (13.0, 23.5) to 32.0% (24.6, 39.4) and 11.1% (6.8, 15.3) to 20.3% (13.9, 26.6). Clinically meaningful improvements in SF-36, pain, fatigue and sleep problems were also maintained throughout the 2 years of abatacept treatment. CONCLUSION: No unique safety observations were reported during open-label exposure. Improvements in the signs and symptoms of rheumatoid arthritis, physical function and health-related quality of life observed after 6 months, were maintained throughout the 2 years in this population with difficult-to-treat disease. TRIAL REGISTRATION NUMBER: NCT00124982.

Experimental analysis of the stratorotational instability in a cylindrical Couette flow.

This study is devoted to the experimental analysis of the stratorotational instability (SRI). This instability affects the classical cylindrical Couette flow when the fluid is stably stratified in the axial direction. In agreement with recent theoretical and numerical analyses, we describe for the first time in detail the destabilization of the stratified flow below the Rayleigh line (i.e., the stability threshold without stratification). We confirm that the unstable modes of the SRI are nonaxisymmetric, oscillatory, and take place as soon as the azimuthal linear velocity decreases along the radial direction. This new instability is relevant for accretion disks.

EULAR report on the use of ultrasonography in painful knee osteoarthritis. Part 2: exploring decision rules for clinical utility.

BACKGROUND: Synovial inflammation (as defined by hypertrophy and effusion) is common in osteoarthritis (OA) and may be important in both pain and structural progression. OBJECTIVE: To determine if decision rules can be devised from clinical findings and ultrasonography (US) to allow recognition of synovial inflammation in patients with painful knee OA. METHODS: A EULAR-ESCISIT cross sectional, multicentre study enrolled subjects with painful OA knee who had clinical, radiographic, and US evaluations. A classification and regression tree (CART) analysis was performed to find combinations of predictor variables that would provide high sensitivity and specificity for clinically detecting synovitis and effusion in individual subjects. A range of definitions for the two key US variables, synovitis and effusion (using different combinations of synovial thickness, depth, and appearance), were also included in exploratory analyses. RESULTS: 600 patients with knee OA were included in the analysis. For both knee synovitis and joint effusion, the sensitivity and specificity were poor, yielding unsatisfactory likelihood ratios (75% sensitivity, 45% specificity, and positive LR of 1.36 for knee synovitis; 71.6% sensitivity, 43.2% specificity, and positive LR of 1.26 for joint effusion). The exploratory analyses did not improve the sensitivity and specificity (demonstrating positive LRs of between 1.26 and 1.57). CONCLUSION: Although it is possible to determine clinical and radiological predictors of OA inflammation in populations, CART analysis could not be used to devise useful clinical decision rules for an individual subject. Thus sensitive imaging techniques such as US remain the most useful tool for demonstrating synovial inflammation of the knee at the individual level.

EULAR report on the use of ultrasonography in painful knee osteoarthritis. Part 1: prevalence of inflammation in osteoarthritis.

OBJECTIVES: To assess the prevalence of inflammation in subjects with chronic painful knee osteoarthritis (OA), as determined by the presence of synovitis or joint effusion at ultrasonography (US); and to evaluate the correlation between synovitis, effusion, and clinical parameters. METHODS: A cross sectional, multicentre, European study was conducted under the umbrella of EULAR-ESCISIT. SUBJECTS: had primary chronic knee OA (ACR criteria) with pain during physical activity >or=30 mm for at least 48 hours. Clinical parameters were collected by a rheumatologist and an US examination of the painful knee was performed by a radiologist or rheumatologist within 72 hours of the clinical examination. Ultrasonographic synovitis was defined as synovial thickness >or=4 mm and diffuse or nodular appearance, and a joint effusion was defined as effusion depth >or=4 mm. RESULTS: 600 patients with painful knee OA were analysed. At US 16 (2.7%) had synovitis alone, 85 (14.2%) had both synovitis and effusion, 177 (29.5%) had joint effusion alone, and 322 (53.7%) had no inflammation according to the definitions employed. Multivariate analysis showed that inflammation seen by US correlated statistically with advanced radiographic disease (Kellgren-Lawrence grade >or=3; odds ratio (OR)=2.20 and 1.91 for synovitis and joint effusion, respectively), and with clinical signs and symptoms suggestive of an inflammatory "flare", such as joint effusion on clinical examination (OR=1.97 and 2.70 for synovitis and joint effusion, respectively) or sudden aggravation of knee pain (OR=1.77 for joint effusion). CONCLUSION: US can detect synovial inflammation and effusion in painful knee OA, which correlate significantly with knee synovitis, effusion, and clinical parameters suggestive of an inflammatory "flare".

Level of acceptability of EULAR recommendations for the management of knee osteoarthritis by practitioners in different European countries.

OBJECTIVE: To evaluate the level of acceptability of the EULAR recommendations for the management of knee osteoarthritis (KOA) in practice. METHODS: A questionnaire was sent to general practitioners, rheumatologists, rehabilitators, and orthopaedic surgeons in five European countries (France, Spain, Belgium, Switzerland, Italy). Practitioners were asked to give their opinion on the 10 EULAR recommendations and on 23 treatment modes for KOA. Practitioners' opinions were compared with those of the expert task force involved in the development of these recommendations. RESULTS: The overall response rate was 10.4% (4204 replies). Results were similar across countries and specialties. Of the 23 treatment modes proposed, only joint lavage and intra-articular (IA) corticosteroid injections were more strongly recommended by the expert task force than by the responders as a whole, while the opposite was true for spa therapy. Principal component analysis showed: (1) some practitioners preferred "hard line" treatments (surgery, IA injections, or non-steroidal anti-inflammatory drugs (NSAIDs)); (2) there was a difference between those prescribing pharmacological (paracetamol) or non-pharmacological measures with low iatrogenicity (exercises, sticks, education), and those prescribing less well validated treatments closer to "alternative" medicine; (3) each specialist tended to advocate modes that they were most familiar with: rheumatologists were more likely to recommend IA injections and NSAIDs; orthopaedic surgeons, surgical procedures; rehabilitators, education and all non-pharmacological modes; general practitioners, spa therapy and opioids. CONCLUSIONS: A multidisciplinary approach is optimal in the management of this chronic disease with its variable course.

Paracetamol in osteoarthritis of the knee.

BACKGROUND: Paracetamol is a recommended symptomatic treatment of osteoarthritis (OA), but in clinical trials sample sizes have been relatively small and variable daily doses of paracetamol have been used. OBJECTIVES: To determine the therapeutic efficacy of paracetamol in OA of the knee and identify predictive factors of clinical response to treatment. METHODS: A double blind, parallel group, placebo controlled trial of analgesic efficacy and safety of paracetamol versus placebo including 779 patients with OA of the knee. Patients were randomly assigned to receive paracetamol 4 g/day (n = 405) or placebo (n = 374) for 6 weeks. Symptomatic OA of the knee was required at inclusion with global pain intensity of the knee during physical activities for the past 24 hours of >or=30 mm on a 100 mm visual analogue scale. The primary end point was a 30% decrease of global pain intensity of the knee. Intention to treat analyses were performed. RESULTS: The percentage of responders did not differ significantly between groups: 52.6% and 51.9% in paracetamol and placebo groups, respectively (p = 0.840). In a subgroup of patients with chronic mechanical knee pain without signs of inflammation (n = 123), the mean change in pain intensity from baseline was 25.2 mm v 15.2 mm, in the paracetamol (n = 63) and placebo (n = 60) groups, respectively-mean difference 10.0 mm; 95% CI 1.0 to 19.0; p = 0.0294. No serious adverse events were attributable to treatment. CONCLUSION: A statistically significant symptomatic effect of oral paracetamol 4 g/day over placebo was not found, suggesting that paracetamol use in symptomatic OA of the knee should be further explored. The tolerability and safety of paracetamol, at the recommended maximum dose of 4 g/day, was confirmed over 6 weeks.

Single and multiple dose pharmacokinetics of acetaminophen (paracetamol) in polymedicated very old patients with rheumatic pain.

OBJECTIVE: To determine whether multiple dosing of acetaminophen would result in drug accumulation in polymedicated elderly patients with rheumatic pain. METHODS: Twelve inpatients (11 women), aged 89 +/- 4 years, weight 59 +/- 10 kg, receiving 3 to 8 concomitant medications, entered the study. Their creatinine clearance according to the Cockroft-Gault formula was 42 +/- 12 ml/min. The pharmacokinetics of 1 g acetaminophen was evaluated after the first dose (D1) and after the last dose (D7) during a 3 times daily regimen of 1 g for 5 consecutive days. RESULTS: The plasma pharmacokinetic profile of acetaminophen did not change significantly at D7 compared to D1. No significant within-patient differences were observed, especially with respect to plasma elimination half-life (2.74 +/- 0.48 and 2.77 +/- 0.32 hours, respectively), area under the concentration-time curve (82.5 +/- 21.1 and 90.1 +/- 15.2 microg x h/ml, respectively), and apparent oral clearance (3.68 +/- 0.85 and 3.28 +/- 0.52 ml/min/kg, respectively). CONCLUSION: No drug accumulation occurred during multiple dosing with acetaminophen in these very old subjects. On the basis of pharmacokinetic data alone, a dose regimen of acetaminophen 1 g tid seems to be appropriate in such patients.

[Tolerance and dependence on opioid analgesics: experimental and clinical aspects]. / Tolérance et dépendance aux antalgiques opioïdes: aspects expérimentaux et cliniques.

Long-term administration of morphine for chronic non-malignant pain continues to be controversial, mainly because of the fear of opioid addiction and abuse. It is important to distinguish three phenomena: tolerance of the analgesic and side-effects of the drug, physical dependence (which is a pure pharmacological event) and addiction (defined as a compulsive drug-related behaviour). Animal studies suggest that similar mechanisms underlie tolerance and physical dependence. These may result from an imbalance between anti- and pro-nociceptive mechanisms. By contrast, the occurrence of an addictive behaviour depends on both different endogenous mechanisms and environmental factors. Clinical data suggest that the use of stable doses of morphine (or other opiates) is common in patients suffering from chronic non-malignant pain. However, drug addiction might develop in 'at-risk patients' and therefore the decision to start long-term treatment with an opiate should be undertaken very cautiously, and ongoing assessment of aberrant drug-related behaviours should be undertaken repeatedly.