396 research outputs found

    Disorder-induced melting of the charge order in thin films of Pr0.5Ca0.5MnO3

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    We have studied the magnetic-field-induced melting of the charge order in thin films of Pr0.5Ca0.5MnO3 (PCMO) films on SrTiO3 (STO) by X-ray diffraction, magnetization and transport measurement. At small thickness (25 nm) the films are under tensile strain and the low-temperature melting fields are of the order of 20 T or more, comparable to the bulk value. With increasing film thickness the strain relaxes, which leads to a strong decrease of the melting fields. For a film of 150 nm, with in-plane and out-of-plane lattice parameters closer to the bulk value, the melting field has reduced to 4 T at 50 K, with a strong increase in the hysteretic behavior and also an increasing fraction of ferromagnetic material. Strain relaxation by growth on a template of YBa2Cu3O(7-delta) or by post-annealing yields similar results with an even stronger reduction of the melting field. Apparently, strained films behave bulk-like. Relaxation leads to increasing suppression of the CO state, presumably due to atomic scale disorder produced by the relaxation process.Comment: 7 pages, 4 fig

    Quantification of Linear and Nonlinear Cardiorespiratory Interactions under Autonomic Nervous System Blockade

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    This paper proposes a methodology to extract both linear and nonlinear respiratory influences from the heart rate variability (HRV), by decomposing the HRV into a respiratory and a residual component. This methodology is based on least-squares support vector machines (LS-SVM) formulated for nonlinear function estimation. From this decomposition, a better estimation of the respiratory sinus arrhythmia (RSA) and the sympathovagal balance (SB) can be achieved. These estimates are first analyzed during autonomic blockade and an orthostatic maneuver, and then compared against the classical HRV and a model that considers only linear interactions. Results are evaluated using surrogate data analysis and they indicate that the classical HRV and the linear model underestimate the cardiorespiratory interactions. Moreover, the linear and nonlinear interactions appear to be mediated by different control mechanisms. These findings will allow to better assess the ANS and to improve the understanding of the interactions within the cardiorespiratory system

    Responding to the Lehman wave : sales forecasting and supply management during the credit crisis

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    In this paper we analyze the strong dip in the manufacturing industry seen at the end of 2008 and provide evidence from various sources that it was caused by cumulative de-stocking, triggered by the bankruptcy of Lehman Brothers. This de-stocking created a giant dampened wave, the so-called Lehman wave. We model the Lehman Wave using system dynamics and validate the model using data from a number of business units and market segments of Royal DSM. We show that the model gives a very good prediction of sales development during the credit crisis. We provide insights into how these results can be used to improve sales forecasting and supply chain management during times of severe crises. We also show that the effects of the current financial crisis are far from over and suggest that our methods be used to predict sales during the year 2010

    Non-Fermi-liquid behavior in Ce(Ru1x_{1-x}Fex_x)2_2Ge2_2: cause and effect

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    We present inelastic neutron scattering measurements on the intermetallic compounds Ce(Ru1x_{1-x}Fex_x)2_2Ge2_2 (xx=0.65, 0.76 and 0.87). These compounds represent samples in a magnetically ordered phase, at a quantum critical point and in the heavy-fermion phase, respectively. We show that at high temperatures the three compositions have the identical response of a local moment system. However, at low temperatures the spin fluctuations in the critical composition are given by non-Fermi-liquid dynamics, while the spin fluctuations in the heavy fermion system show a simple exponential decay in time. In both compositions, the lifetime of the fluctuations is determined solely by the distance to the quantum critical point. We discuss the implications of these observations regarding the possible origins of non-Fermi-liquid behavior in this system.Comment: 4 figures, submitted to PR

    Proximity effects in the superconductor / heavy fermion bilayer system Nb / CeCu_6

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    We have investigated the proximity effect between a superconductor (Nb) and a 'Heavy Fermion' system (CeCu_6) by measuring critical temperatures TcT_c and parallel critical fields H_{c2}^{\parallel}(T) of Nb films with varying thickness deposited on 75 nm thick films of CeCu_6, and comparing the results with the behavior of similar films deposited on the normal metal Cu. For Nb on CeCu_6 we find a strong decrease of T_c with decreasing Nb thickness and a finite critical thickness of the order of 10 nm. Also, dimensional crossovers in H_{c2}^{\parallel}(T) are completely absent, in strong contrast with Nb/Cu. Analysis of the data by a proximity effect model based on the Takahashi-Tachiki theory shows that the data can be explained by taking into account both the high effective mass (or low electronic diffusion constant), {\it and} the large density of states at the Fermi energy which characterize the Heavy Fermion metal.Comment: 7 pages, 2 figure. Manuscript has been submitted to a refereed journa

    A spatially-structured PCG method for content diversity in a Physics-based simulation game

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    This paper presents a spatially-structured evolutionary algorithm (EA) to procedurally generate game maps of di ferent levels of di ficulty to be solved, in Gravityvolve!, a physics-based simulation videogame that we have implemented and which is inspired by the n- body problem, a classical problem in the fi eld of physics and mathematics. The proposal consists of a steady-state EA whose population is partitioned into three groups according to the di ficulty of the generated content (hard, medium or easy) which can be easily adapted to handle the automatic creation of content of diverse nature in other games. In addition, we present three fitness functions, based on multiple criteria (i.e:, intersections, gravitational acceleration and simulations), that were used experimentally to conduct the search process for creating a database of maps with di ferent di ficulty in Gravityvolve!.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Timing measurements with a 3D silicon sensor on Timepix3 in a 180 GeV/<i>c</i> hadron beam

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    Test beam measurements have been carried out with a 3D sensor on a Timepix3 ASIC and the time measurements are presented. The measurements are compared to those of a thin planar sensor on Timepix3. It is shown that for a perpendicularly incident beam the time resolution of both detectors is dominated by the Timepix3 front-end. The 3D detector is dominated by the time-to-digital conversion whereas the analog front-end jitter also gives a significant contribution for the thin planar detector. The 3D detector reaches an overall time resolution of 567 ± 6 ps compared to 683 ± 8 ps for the thin planar detector. For a grazing angle beam, however, the thin planar detector achieves a better time resolution because it has a lower pixel capacitance, and therefore suffers less from jitter in the analog front-end for the low charge signals that mainly occur in this type of measurement. Finally, it is also shown that the 3D and thin planar detector can achieve time resolutions for large clusters of about 100 ps and 250 ps, respectively, by combining many single hit measurements

    Efficacy and safety of filgotinib in methotrexate-naive patients with rheumatoid arthritis with poor prognostic factors: post hoc analysis of FINCH 3

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    OBJECTIVE: This analysis evaluated efficacy and safety of filgotinib, a Janus-associated kinase 1-preferential inhibitor, in methotrexate (MTX)-naive patients with rheumatoid arthritis (RA) with multiple poor prognostic factors (PPFs). METHODS: This was a post hoc analysis of the phase III, randomised, double-blind, active-controlled, FINCH 3 study (clinicaltrials.gov NCT02886728). Patients received once-daily oral filgotinib 200 or 100 mg plus once-weekly oral MTX ≤20 mg (FIL200 + MTX and FIL100 + MTX), filgotinib 200 mg monotherapy (FIL200), or oral MTX monotherapy (MTX-mono) for up to 52 weeks. PPFs investigated were seropositivity for rheumatoid factor or anticyclic citrullinated peptide antibodies, high-sensitivity C reactive protein (CRP) ≥4 mg/L, Disease Activity Score in 28 joints with CRP (DAS28(CRP)) >5.1, and presence of erosions. Filgotinib efficacy and safety in patients with all four PPFs at baseline were explored versus MTX-mono within this subgroup and compared informally with the overall population. RESULTS: Of 1249 patients in FINCH 3, 510 (40.8%) had all PPFs. Efficacy of FIL200 + MTX among these patients was comparable to the overall population, with higher rates of 20%/50%/70% improvement from baseline by American College of Rheumatology criteria, DAS28(CRP) <2.6, and remission; greater improvement in physical function and pain; and better inhibition of structural damage relative to MTX-mono. FIL100 + MTX and FIL200 were not consistently more efficacious versus MTX-mono. Safety of filgotinib in patients with PPFs was comparable to the overall population; no new safety signals were observed. CONCLUSION: FIL200 + MTX efficacy and safety in patients with multiple PPFs were similar to the overall population
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