2,118 research outputs found

    Nested (inverse) binomial sums and new iterated integrals for massive Feynman diagrams

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    Nested sums containing binomial coefficients occur in the computation of massive operator matrix elements. Their associated iterated integrals lead to alphabets including radicals, for which we determined a suitable basis. We discuss algorithms for converting between sum and integral representations, mainly relying on the Mellin transform. To aid the conversion we worked out dedicated rewrite rules, based on which also some general patterns emerging in the process can be obtained.Comment: 13 pages LATEX, one style file, Proceedings of Loops and Legs in Quantum Field Theory -- LL2014,27 April 2014 -- 02 May 2014 Weimar, German

    A differential algebra based importance sampling method for impact probability computation on Earth resonant returns of Near Earth Objects

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    A differential algebra based importance sampling method for uncertainty propagation and impact probability computation on the first resonant returns of Near Earth Objects is presented in this paper. Starting from the results of an orbit determination process, we use a differential algebra based automatic domain pruning to estimate resonances and automatically propagate in time the regions of the initial uncertainty set that include the resonant return of interest. The result is a list of polynomial state vectors, each mapping specific regions of the uncertainty set from the observation epoch to the resonant return. Then, we employ a Monte Carlo importance sampling technique on the generated subsets for impact probability computation. We assess the performance of the proposed approach on the case of asteroid (99942) Apophis. A sensitivity analysis on the main parameters of the technique is carried out, providing guidelines for their selection. We finally compare the results of the proposed method to standard and advanced orbital sampling techniques

    Parameterized partial element equivalent circuit method for sensitivity analysis of multiport systems

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    This paper presents a new technique to perform parameterized sensitivity analyses of systems that depend on multiple design parameters, such as layout and substrate features. It uses the electromagnetic (EM) method called partial element equivalent circuit to compute state space matrices at a set of design space points. These EM matrices are interpolated as functions of the design parameters. The proposed interpolation scheme allows the computation of the derivatives of the matrices, which are needed to perform the sensitivity analysis. An extensive study of the required stability and passivity properties of the system involved in the parameterized sensitivity analysis is presented. Pertinent numerical results demonstrate the robustness, accuracy, and efficiency of the proposed methodology

    Muon spin spectroscopy: magnetism, soft matter and the bridge between the two

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    LS would like to acknowledge financial support from the Swiss National Science Foundation, grant numbers PBFRP2-138632 and PBFRP2-142820. AD would like to acknowledge financial support from the UK Engineering and Physical Sciences Research Council, grant number EP/G054568/1, the European Union Seventh Framework Programme project NMP3-SL- 2011-263104 ‘HINTS’ and the European Research Council project ‘Muon Spin Spectroscopy of Excited States (MuSES)’ proposal number 307593LS would like to acknowledge financial support from the Swiss National Science Foundation, grant numbers PBFRP2-138632 and PBFRP2-142820. AD would like to acknowledge financial support from the UK Engineering and Physical Sciences Research Council, grant number EP/G054568/1, the European Union Seventh Framework Programme project NMP3-SL- 2011-263104 ‘HINTS’ and the European Research Council project ‘Muon Spin Spectroscopy of Excited States (MuSES)’ proposal number 307593LS would like to acknowledge financial support from the Swiss National Science Foundation, grant numbers PBFRP2-138632 and PBFRP2-142820. AD would like to acknowledge financial support from the UK Engineering and Physical Sciences Research Council, grant number EP/G054568/1, the European Union Seventh Framework Programme project NMP3-SL- 2011-263104 ‘HINTS’ and the European Research Council project ‘Muon Spin Spectroscopy of Excited States (MuSES)’ proposal number 30759

    Blood Omega-3 Fatty Acids Are Inversely Associated With Albumin-Creatinine Ratio in Young and Healthy Adults (The Omega-Kid Study).

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    Background: Omega-3 fatty acids are associated with a lower risk of cardiovascular disease (CVD) and with beneficial effects on CV risk factors. The albumin-creatinine ratio (ACR) is a risk factor for CVD, all-cause mortality and accelerated glomerular filtration rate (GFR) decline in the general population. We aimed to investigate the association between n-3 PUFAS and ACR in heathy individuals with preserved GFR. Design and Methods: The present cross-sectional analysis is part of the GAPP study, a population-based cohort of healthy adults aged 25-41 years. Individuals with known CVD, diabetes, or a BMI >35 kg/m2 were excluded. eGFR was calculated according to the combined Creatinine/Cystatin C CKD-EPI formula. ACR was obtained from a fasting morning urine sample. The Omega-3 Index (relative amount of EPA and DHA of total fatty acids in %) was obtained from whole blood aliquots. Results: Overall, 2001 participants (median age 37 years IQR 31; 40, 53% female) were included in this analysis. Median Omega-3 Index was 4.59 (IQR 4.06; 5.25) and median eGFR 111 ml/min/1.73 m2 (IQR 103; 118). Median ACR was 0.14 mg/mmol (IQR 0; 0.43). We found a significant inverse association of the Omega-3 Index with ACR (ratio 0.84, 95%CI 0.73-0.96; p = 0.011) which remained after comprehensive adjustment (ratio 0.86, 95%CI 0.74-1.00; p = 0.048). No association of the Omega-3 Index with eGFR was found. The adjusted difference in eGFR per 1-unit increase in Omega3-Index was -0.21 (95%CI -0.76; 0.35; p = 0.47). Conclusions: A higher Omega-3 Index was significantly associated with lower ACR in this young and healthy population with preserved eGFR. Omega-3 fatty acids may exhibit cardio- and nephroprotective effects in healthy individuals through modulation of ACR
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