5,824 research outputs found

    Obesity and rates of clinical remission and low MRI inflammation in rheumatoid arthritis

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    Objectives: Obesity has been proposed as a risk factor for refractory rheumatoid arthritis (RA). We evaluated the impact of obesity on achieving clinical and imaging definitions of low disease activity. Methods: This study evaluated 470 patients with RA from GO-BEFORE and GO-FORWARD randomised clinical trials. Included patients had blinded clinical disease activity measures and MRI at baseline, 24 and 52 weeks. Synovitis, osteitis and total inflammation scores were determined using the RA MRI scoring system. Multivariable logistic regression analyses compared odds of achieving Disease Activity Score using 28 joints and C-reactive protein (DAS28-CRP) remission, low component measures, or low MRI inflammation measures at 24 weeks in patients with obesity versus no obesity. Results: At 24 weeks, patients with obesity were significantly less likely to achieve DAS28(CRP) remission (OR 0.47; 95% CI 0.24 to 0.92, p=0.03). In contrast, patients with obesity had similar odds of achieving low synovitis (OR 0.94; 95% CI 0.51 to 1.72, p=0.84) and inflammation scores (OR 1.16; 95% CI 0.61 to 2.22, p=0.64) and greater odds of achieving low osteitis scores (OR 2.06; 95% CI 1.10 to 3.84, p=0.02) versus normal weight patients. Conclusions: Patients with RA and obesity have lower rates of DAS28 remission but similar rates of low MRI activity compared with patients without obesity, suggesting that obesity and its associated comorbidities can bias clinical disease activity measures. Trial registration number: NCT00361335 and NCT00264550; Post-results

    Beyond Correlation Filters: Learning Continuous Convolution Operators for Visual Tracking

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    Discriminative Correlation Filters (DCF) have demonstrated excellent performance for visual object tracking. The key to their success is the ability to efficiently exploit available negative data by including all shifted versions of a training sample. However, the underlying DCF formulation is restricted to single-resolution feature maps, significantly limiting its potential. In this paper, we go beyond the conventional DCF framework and introduce a novel formulation for training continuous convolution filters. We employ an implicit interpolation model to pose the learning problem in the continuous spatial domain. Our proposed formulation enables efficient integration of multi-resolution deep feature maps, leading to superior results on three object tracking benchmarks: OTB-2015 (+5.1% in mean OP), Temple-Color (+4.6% in mean OP), and VOT2015 (20% relative reduction in failure rate). Additionally, our approach is capable of sub-pixel localization, crucial for the task of accurate feature point tracking. We also demonstrate the effectiveness of our learning formulation in extensive feature point tracking experiments. Code and supplementary material are available at http://www.cvl.isy.liu.se/research/objrec/visualtracking/conttrack/index.html.Comment: Accepted at ECCV 201

    Obesity and rates of clinical remission and low MRI inflammation in rheumatoid arthritis

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    Objectives: Obesity has been proposed as a risk factor for refractory rheumatoid arthritis (RA). We evaluated the impact of obesity on achieving clinical and imaging definitions of low disease activity. Methods: This study evaluated 470 patients with RA from GO-BEFORE and GO-FORWARD randomised clinical trials. Included patients had blinded clinical disease activity measures and MRI at baseline, 24 and 52 weeks. Synovitis, osteitis and total inflammation scores were determined using the RA MRI scoring system. Multivariable logistic regression analyses compared odds of achieving Disease Activity Score using 28 joints and C-reactive protein (DAS28-CRP) remission, low component measures, or low MRI inflammation measures at 24 weeks in patients with obesity versus no obesity. Results: At 24 weeks, patients with obesity were significantly less likely to achieve DAS28(CRP) remission (OR 0.47; 95% CI 0.24 to 0.92, p=0.03). In contrast, patients with obesity had similar odds of achieving low synovitis (OR 0.94; 95% CI 0.51 to 1.72, p=0.84) and inflammation scores (OR 1.16; 95% CI 0.61 to 2.22, p=0.64) and greater odds of achieving low osteitis scores (OR 2.06; 95% CI 1.10 to 3.84, p=0.02) versus normal weight patients. Conclusions: Patients with RA and obesity have lower rates of DAS28 remission but similar rates of low MRI activity compared with patients without obesity, suggesting that obesity and its associated comorbidities can bias clinical disease activity measures. Trial registration number: NCT00361335 and NCT00264550; Post-results

    Baseline Objective Inflammation by Magnetic Resonance Imaging as a Predictor of Therapeutic Benefit in Early Rheumatoid Arthritis With Poor Prognosis

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    Objective: High magnetic resonance imaging (MRI )–detected inflammation is associated with greater progression and poorer outcomes in rheumatoid arthritis (RA ). This analysis aimed to determine if baseline MRI inflammation was related to clinical response and remission in the Assessing Very Early Rheumatoid arthritis Treatment (AVERT ) study. Methods: AVERT was a phase III b, randomized, controlled trial with a 12‐month, double‐blind treatment period enrolling patients with early (≤2 years' duration), anti‐citrullinated peptide–positive methotrexate (MTX )‐naive RA . In this post hoc analysis, patients in the abatacept plus MTX (n = 114) and MTX (n = 111) arms with available MRI results were stratified into low and high baseline MRI inflammation groups based on previously developed cutoffs of synovitis and osteitis on unilateral hand–wrist contrast‐enhanced MRI . Simplified Disease Activity Index (SDAI ) remission (≤3.3), Clinical Disease Activity Index (CDAI ) remission (≤2.8), Boolean remission, and Disease Activity Score in 28 joints using the C‐reactive protein level (<2.6) were assessed. Results: Overall, 100 of 225 patients (44.4%) had high baseline MRI inflammation. In patients with high baseline MRI inflammation, a significantly greater proportion achieved remission at 12 months with abatacept plus MTX versus MTX across SDAI (45.1% versus 16.3%; P = 0.0022), CDAI (47.1% versus 20.4%; P = 0.0065), and Boolean indices (39.2% versus 16.3%; P = 0.0156). In patients with low baseline MRI inflammation, remission rates were not significantly different with abatacept plus MTX versus MTX (SDAI : 39.7% versus 32.3%; P = 0.4961). Conclusion: In seropositive, MTX ‐naive patients with early RA and presence of objectively measured high inflammation by MRI , indicating poor prognosis, remission rates were higher with abatacept plus MTX treatment versus MTX

    Quantum corrections to the gravitational backreaction

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    Effective field theory techniques are used to study the leading order quantum corrections to the gravitational wave backreaction. The effective stress-energy tensor is calculated and it is shown that it has a non-vanishing trace that contributes to the cosmological constant. By comparing the result obtained with LIGO’s data, the first bound on the amplitude of the massive mode is found: ϵ<1.4×10 −33

    Theory of dynamic crack branching in brittle materials

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    The problem of dynamic symmetric branching of an initial single brittle crack propagating at a given speed under plane loading conditions is studied within a continuum mechanics approach. Griffith's energy criterion and the principle of local symmetry are used to determine the cracks paths. The bifurcation is predicted at a given critical speed and at a specific branching angle: both correlated very well with experiments. The curvature of the subsequent branches is also studied: the sign of TT, with TT being the non singular stress at the initial crack tip, separates branches paths that diverge from or converge to the initial path, a feature that may be tested in future experiments. The model rests on a scenario of crack branching with some reasonable assumptions based on general considerations and in exact dynamic results for anti-plane branching. It is argued that it is possible to use a static analysis of the crack bifurcation for plane loading as a good approximation to the dynamical case. The results are interesting since they explain within a continuum mechanics approach the main features of the branching instabilities of fast cracks in brittle materials, i.e. critical speeds, branching angle and the geometry of subsequent branches paths.Comment: 41 pages, 15 figures. Accepted to International Journal of Fractur

    P-odd and CP-odd Four-Quark Contributions to Neutron EDM

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    In a class of beyond-standard-model theories, CP-odd observables, such as the neutron electric dipole moment, receive significant contributions from flavor-neutral P-odd and CP-odd four-quark operators. However, considerable uncertainties exist in the hadronic matrix elements of these operators strongly affecting the experimental constraints on CP-violating parameters in the theories. Here we study their hadronic matrix elements in combined chiral perturbation theory and nucleon models. We first classify the operators in chiral representations and present the leading-order QCD evolutions. We then match the four-quark operators to the corresponding ones in chiral hadronic theory, finding symmetry relations among the matrix elements. Although this makes lattice QCD calculations feasible, we choose to estimate the non-perturbative matching coefficients in simple quark models. We finally compare the results for the neutron electric dipole moment and P-odd and CP-odd pion-nucleon couplings with the previous studies using naive factorization and QCD sum rules. Our study shall provide valuable insights on the present hadronic physics uncertainties in these observables.Comment: 40 pages, 7 figures. This is the final version. A discussion of the uncertainty of the calculation is adde
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