141 research outputs found

    Aging, rejuvenation, and memory effects in short-range Ising spin glass: Cu0.5_{0.5}Co0.5_{0.5}Cl2_{2}-FeCl3_{3} graphite bi-intercalation compound

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    Non-equilibrium aging dynamics in 3D Ising spin glass Cu0.5_{0.5}Co0.5_{0.5}Cl2_{2}-FeCl3_{3} GBIC has been studied by zero-field cooled (ZFC) magnetization and low frequency AC magnetic susceptibility (f=0.05f = 0.05 Hz), where Tg=3.92±0.11T_{g} = 3.92 \pm 0.11 K. The time dependence of the relaxation rate S(t)=(1/H)S(t) = (1/H)dMZFC/M_{ZFC}/dlnt\ln t for the ZFC magnetization after the ZFC aging protocol, shows a peak at a characteristic time tcrt_{cr} near a wait time twt_{w} (aging behavior), corresponding to a crossover from quasi equilibrium dynamics to non-equilibrium. The time tcrt_{cr} strongly depends on twt_{w}, temperature (TT), magnetic field (HH), and the temperature shift (ΔT\Delta T). The rejuvenation effect is observed in both χ\chi^{\prime} and χ\chi^{\prime\prime} under the TT-shift and HH-shift procedures. The memory of the specific spin configurations imprinted during the ZFC aging protocol can be recalled when the system is re-heated at a constant heating rate. The aging, rejuvenation, and memory effects observed in the present system are discussed in terms of the scaling concepts derived from numerical studies on 3D Edwards-Anderson spin glass model.Comment: 14 pages, 14 figures; Eur. Phys. J. B accepted for publicatio

    Pore wall corrugation effect on the dynamics of adsorbed H 2 studied by in situ quasi elastic neutron scattering Observation of two timescaled diffusion

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    The self diffusion mechanisms for adsorbed H2 in different porous structures are investigated with in situ quasi elastic neutron scattering method at a temperature range from 50 K to 100 K and at various H2 loadings. The porous structures of the carbon materials have been characterized by sorption analysis with four different gases and the results are correlated with previous in depth analysis with small angle neutron scattering method. Thus, an investigation discussing the effect of pore shape and size on the nature of adsorbed H2 self diffusion is performed. It is shown that H2 adsorbed in nanometer scale pores is self diffusing in two distinguishable timescales. The effect of the pore, pore wall shape and corrugation on the fraction of confined and more mobile H2 is determined and analyzed. The increased corrugation of the pore walls is shown to have a stronger confining effect on the H2 motions. The difference of self diffusional properties of the two H2 components are shown to be smaller when adsorbed in smoother walled pores. This is attributed to the pore wall corrugation effect on the homogeneity of formed adsorbed layer

    Progression and Regression: Distinct Developmental Patterns of Diabetic Retinopathy in Patients With Type 2 Diabetes Treated in the Diabetes Care System West-Friesland, the Netherlands

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    OBJECTIVE: To identify distinct developmental patterns of diabetic retinopathy (DR) and assess the risk factor levels of patients in these clusters. RESEARCH DESIGN AND METHODS: A cohort of 3,343 patients with type 2 diabetes mellitus (T2DM) monitored and treated in the Diabetes Care System West-Friesland, the Netherlands, was followed from 2 to 6 years. Risk factors were measured, and two-field fundus photographs were taken annually and graded according to the EURODIAB study group. Latent class growth modeling was used to identify distinct developmental patterns of DR over time. RESULTS: Five clusters of patients with distinct developmental patterns of DR were identified: A, patients without any signs of DR (88.9%); B, patients with a slow regression from minimal background to no DR (4.9%); C, patients with a slow progression from minimal background to moderate nonproliferative DR (4.0%); D, patients with a fast progression from minimal or moderate nonproliferative to (pre)proliferative or treated DR (1.4%); and E, patients with persistent proliferative DR (0.8%). Patients in clusters A and B were characterized by lower risk factor levels, such as diabetes duration, HbA(1c), and systolic blood pressure compared with patients in progressive clusters (C-E). CONCLUSIONS: Clusters of patients with T2DM with markedly different patterns of DR development were identified, including a cluster with regression of DR. These clusters enable a more detailed examination of the influence of various risk factors on DR

    Disentangling Income Inequality and the Redistributive Effect of Social Transfers and Taxes in 36 LIS Countries

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    Clinical Outcomes With a Repositionable Self-Expanding Transcatheter Aortic Valve Prosthesis: The International FORWARD Study

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    Background Clinical outcomes in large patient populations from real-world clinical practice with a next-generation self-expanding transcatheter aortic valve are lacking. Objectives This study sought to document the clinical and device performance outcomes of transcatheter aortic valve replacement (TAVR) with a next-generation, self-expanding transcatheter heart valve (THV) system in patients with severe symptomatic aortic stenosis (AS) in routine clinical practice. Methods The FORWARD (CoreValve Evolut R FORWARD) study is a prospective, single-arm, multinational, multicenter, observational study. An independent clinical events committee adjudicated safety endpoints based on Valve Academic Research Consortium-2 definitions. An independent echocardiographic core laboratory evaluated all echocardiograms. From January 2016 to December 2016, TAVR with the next-generation self-expanding THV was attempted in 1,038 patients with symptomatic, severe AS at 53 centers on 4 continents. Results Mean age was 81.8 ± 6.2 years, 64.9% were women, the mean Society of Thoracic Surgeons Predicted Risk of Mortality was 5.5 ± 4.5%, and 33.9% of patients were deemed frail. The repositioning feature of the THV was applied in 25.8% of patients. A single valve was implanted in the proper anatomic location in 98.9% of patients. The mean aortic valve gradient was 8.5 ± 5.6 mm Hg, and moderate or severe aortic regurgitation was 1.9% at discharge. All-cause mortality was 1.9%, and disabling stroke occurred in 1.8% at 30 days. The expected-to-observed early surgical mortality ratio was 0.35. A pacemaker was implanted in 17.5% of patients. Conclusions TAVR using the next-generation THV is clinically safe and effective for treating older patients with severe AS at increased operative risk. (CoreValve Evolut R FORWARD Study [FORWARD]; NCT02592369
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