1,152 research outputs found

    Partial nonlinear reciprocity breaking through ultrafast dynamics in a random photonic medium

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    We demonstrate that ultrafast nonlinear dynamics gives rise to reciprocity breaking in a random photonic medium. Reciprocity breaking is observed via the suppression of coherent backscattering, a manifestation of weak localization of light. The effect is observed in a pump-probe configuration where the pump induces an ultrafast step-change of the refractive index during the dwell time of the probe light in the material. The dynamical suppression of coherent backscattering is reproduced well by a multiple scattering Monte Carlo simulation. Ultrafast reciprocity breaking provides a distinct mechanism in nonlinear optical media which opens up avenues for the active manipulation of mesoscopic transport, random lasers, and photon localization.Comment: 5 pages, 4 figure

    Ferromagnetic domain structure of La0.78Ca0.22MnO3 single crystals

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    The magneto-optical technique has been employed to observe spontaneous ferromagnetic domain structures in La0.78Ca0.22MnO3 single crystals. The magnetic domain topology was found to be correlated with the intrinsic twin structure of the investigated crystals. With decreasing temperature the regular network of ferromagnetic domains undergoes significant changes resulting in apparent rotation of the domain walls in the temperature range of 70–150 K. The apparent rotation of the domain walls can be understood in terms of the Jahn-Teller deformation of the orthorhombic unit cell, accompanied by additional twinning

    Long-term follow-up of 17 patients with childhood Pompe disease treated with enzyme replacement therapy

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    Objectives: Pompe disease is a progressive metabolic myopathy for which enzyme replacement therapy (ERT) was approved in 2006. While various publications have examined the effects of ERT in classic-infantile patients and in adults, little has been published on ERT in children with non-classic presentations. Study design: This prospective study was conducted from June 1999 to May 2015. Seventeen patients from various countries participated. Outcome measures comprised muscle function (6-minute walk test, quick motor-function test (QMFT)), muscle strength (hand-held dynamometry; manual muscle testing), and lung function (FVC sitting and supine). For each outcome measure, we used linear mixed-effects models to calculate the difference at group level between the start of therapy and 7 years of ERT. Patients’ individual responses over time were also evaluated. Results: Eleven males and six females started ERT at ages between 1.1 and 16.4 years (median 11.9 years); 82% of them carried the common c.-32-13T > G GAA gene variant on one allele. At group level, distance walked increased by 7.4 percentage points (p < 0.001) and QMFT scores increased by 9.2 percentage points (p = 0.006). Muscle strength scores seemed to remain stable. Results on lung function were more variable. Patients’ individual data show that the proportion of patients who stabilized or improved during treatment ranged between 56 and 69% for lung function outcomes and between 71 and 93% for muscle strength and muscle function outcomes. Conclusions: We report a positive effect of ERT in patients with childhood Pompe disease at group level. For some patients

    Ferromagnetic Domain Structure of La0.78Ca0.22MnO3 Single Crystals

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    The magneto-optical technique has been employed to observe spontaneous ferromagnetic domain structures in La0.78Ca0.22MnO3 single crystals. The magnetic domain topology was found to be correlated with the intrinsic twin structure of the investigated crystals. With decreasing temperature the regular network of ferromagnetic domains undergoes significant changes resulting in apparent rotation of the domain walls in the temperature range of 70-150 K. The apparent rotation of the domain walls can be understood in terms of the Jahn-Teller deformation of the orthorhombic unit cell, accompanied by additional twinning.Comment: 7 pages, 5 figures, to be published in PR

    Defect-unbinding and the Bose-glass transition in layered superconductors

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    The low-field Bose-glass transition temperature in heavy-ion irradiated Bi_2Sr_2CaCu_2O_8+d increases progressively with increasing density of irradiation-induced columnar defects, but saturates for densities in excess of 1.5 x10^9 cm^-2. The maximum Bose-glass temperature corresponds to that above which diffusion of two-dimensional pancake vortices between different vortex lines becomes possible, and above which the ``line-like'' character of vortices is lost. We develop a description of the Bose-glass line that is in excellent quantitative agreement with the experimental line obtained for widely different values of track density and material parameters.Comment: 4 pages, 4 figures, submitted to Phys. Rev. Let

    The magnetization of PrFeAsO0.60_{0.60}F$_{0.12} sueprconductor

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    The magnetization of the PrFeAsO0.60_{0.60}F0.12_{0.12} polycrystalline sample has been measured as functions of temperature and magnetic field (H)(H). The observed total magnetization is the sum of a superconducting irreversible magnetization (MsM_s) and a paramagnetic magnetization (MpM_p). Analysis of dc susceptibility χ(T)\chi(T) in the normal state shows that the paramagnetic component of magnetization comes from the Pr+3^{+3} magnetic moments. The intragrain critical current density (JL)(J_L) derived from the magnetization measurement is large. The JL(H)J_L(H) curve displays a second peak which shifts towards the high-field region with decreasing temperature. In the low-field region, a plateau up to a field HH^* followed by a power law H5/8H^{-5/8} behavior of JL(H)J_L(H) is the characteristic of the strong pinning. A vortex phase diagram for the present superconductor has been obtained from the magnetization and resistivity data.Comment: A revised version with modified title,8 pages, 7 figure

    Functional polymorphisms of macrophage migration inhibitory factor as predictors of morbidity and mortality of pneumococcal meningitis.

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    Pneumococcal meningitis is the most frequent and critical type of bacterial meningitis. Because cytokines play an important role in the pathogenesis of bacterial meningitis, we examined whether functional polymorphisms of the proinflammatory cytokine macrophage migration inhibitory factor (MIF) were associated with morbidity and mortality of pneumococcal meningitis. Two functional MIF promoter polymorphisms, a microsatellite (-794 CATT5-8; rs5844572) and a single-nucleotide polymorphism (-173 G/C; rs755622) were genotyped in a prospective, nationwide cohort of 405 patients with pneumococcal meningitis and in 329 controls matched for age, gender, and ethnicity. Carriages of the CATT7 and -173 C high-expression MIF alleles were associated with unfavorable outcome (P= 0.005 and 0.003) and death (P= 0.03 and 0.01). In a multivariate logistic regression model, shock [odds ratio (OR) 26.0, P= 0.02] and carriage of the CATT7 allele (OR 5.12,P= 0.04) were the main predictors of mortality. MIF levels in the cerebrospinal fluid were associated with systemic complications and death (P= 0.0002). Streptococcus pneumoniae strongly up-regulated MIF production in whole blood and transcription activity of high-expression MIF promoter Luciferase reporter constructs in THP-1 monocytes. Consistent with these findings, treatment with anti-MIF immunoglogulin G (IgG) antibodies reduced bacterial loads and improved survival in a mouse model of pneumococcal pneumonia and sepsis. The present study provides strong evidence that carriage of high-expression MIF alleles is a genetic marker of morbidity and mortality of pneumococcal meningitis and also suggests a potential role for MIF as a target of immune-modulating adjunctive therapy

    Slab Driven Quaternary Rock‐Uplift and Topographic Evolution in the Northern‐Central Apennines From Linear Inversion of the Drainage System

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    Investigating rock-uplift variations in time and space provides insights into the processes driving mountain-belt evolution. The Apennine Mountains of Italy underwent substantial Quaternary rock uplift that shaped the present-day topography. Here, we present linear river-profile inversions for 28 catchments draining the eastern flank of the Northern-Central Apennines to reconstruct rock-uplift histories. We calibrated these results by estimating an erodibility coefficient (K) from incision rates and catchment-averaged erosion rates obtained from cosmogenic-nuclide data, and we tested whether a uniform or variable K produces a rock-uplift model that satisfactorily fits independent geochronological constraints. We employ a landscape-evolution model to demonstrate that our inversion results are reliable despite substantial seaward lengthening of the catchments during uplift. Our findings suggest that a rock-uplift pulse started around 3.0-2.5 Ma, coinciding with the onset of extension in the Apennines, and migrated southward at a rate of similar to 90 km/Myr. The highest reconstructed rock-uplift rates (&gt;1 km/Myr) occur in the region encompassing the highest Apennine massifs. These results are consistent with numerical models and field evidence from other regions exhibiting rapid rock-uplift pulses and uplift migration related to slab break-off. Our results support the hypothesis of break-off of the Adria slab under the central Apennines and its southward propagation during the Quaternary. Moreover, the results suggest a renewed increase in rock-uplift rates after the Middle Pleistocene along the Adriatic coast, coeval with recent uplift acceleration along the eastern coast of southern Italy in the Apulian foreland
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