10,647 research outputs found

    Study of the Brazil and Falkland currents using their images of Nimbus 5 and oceanographic data in 1972 - 1973

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    The Western Edge of the Sub-tropical Convergence of the South-western Atlantic Ocean, called the Front, which is a thermal discontinuity between the Brazil and Falkland Currents, was studied utilizing the Temperature Humidity Infrared Radiometer (THIR) of Nimbus V in the 10.5 to 12.5 micrometers channel and historical oceanographic data. Some important results obtained are: the oceanographic Front could be detected from Nimbus THIR data; oceanographic charts showed that the transition zone where the Brazil and the Falkland Currents meet was the Front detected from satellite data; ocean current speeds calculated with THIR data were of the same order of magnitude as those calculated oceanographically; fisheries statistics for Pargo Roseo showed that the maximum catches were in September of 1973, in the period when the Front was observed most distinctly and clearly. The results showed the great potentiality of satellite data to study surface thermal structures, surface currents and oceanic fisheries

    Neutron spin-echo study of the critical dynamics of spin-5/2 antiferromagnets in two and three dimensions

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    We report a neutron spin-echo study of the critical dynamics in the S=5/2S=5/2 antiferromagnets MnF2_2 and Rb2_2MnF4_4 with three-dimensional (3D) and two-dimensional (2D) spin systems, respectively, in zero external field. Both compounds are Heisenberg antiferromagnets with a small uniaxial anisotropy resulting from dipolar spin-spin interactions, which leads to a crossover in the critical dynamics close to the N\'eel temperature, TNT_N. By taking advantage of the μeV\mu\text{eV} energy resolution of the spin-echo spectrometer, we have determined the dynamical critical exponents zz for both longitudinal and transverse fluctuations. In MnF2_2, both the characteristic temperature for crossover from 3D Heisenberg to 3D Ising behavior and the exponents zz in both regimes are consistent with predictions from the dynamical scaling theory. The amplitude ratio of longitudinal and transverse fluctuations also agrees with predictions. In Rb2_2MnF4_4, the critical dynamics crosses over from the expected 2D Heisenberg behavior for T≫TNT\gg T_N to a scaling regime with exponent z=1.387(4)z = 1.387(4), which has not been predicted by theory and may indicate the influence of long-range dipolar interactions

    Epitaxial growth of deposited amorphous layer by laser annealing

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    We demonstrate that a single short pulse of laser irradiation of appropriate energy is capable of recrystallizing in open air an amorphous Si layer deposited on a (100) single-crystal substrate into an epitaxial layer. The laser pulse annealing technique is shown to overcome the interfacial oxide obstacle which usually leads to polycrystalline formation in normal thermal annealing

    Inhibition of dengue virus replication by novel inhibitors of RNA-dependent RNA polymerase and protease activities

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    Dengue virus (DENV) is the leading mosquito-transmitted viral infection in the world. With more than 390 million new infections annually, and up to 1 million clinical cases with severe disease manifestations, there continues to be a need to develop new antiviral agents against dengue infection. In addition, there is no approved anti-DENV agents for treating DENV-infected patients. In the present study, we identified new compounds with anti-DENV replication activity by targeting viral replication enzymes – NS5, RNA-dependent RNA polymerase (RdRp) and NS3 protease, using cell-based reporter assay. Subsequently, we performed an enzyme-based assay to clarify the action of these compounds against DENV RdRp or NS3 protease activity. Moreover, these compounds exhibited anti-DENV activity in vivo in the ICR-suckling DENV-infected mouse model. Combination drug treatment exhibited a synergistic inhibition of DENV replication. These results describe novel prototypical small anti-DENV molecules for further development through compound modification and provide potential antivirals for treating DENV infection and DENV-related diseases
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