7,132 research outputs found
Nontyphoidal Salmonella Bacteremia in Previously Healthy Children: Analysis of 199 Episodes
No full textHighly efficient laser-driven Compton gamma-ray source
No full textThe recent advancement of high-intensity lasers has made all-optical Compton scattering become a promising way to produce ultrashort brilliant gamma-rays in an ultra-compact system. However, so far achieved Compton gamma-ray sources are limited by low conversion efficiency and spectral intensity. Here we present a highly efficient gamma photon emitter obtained by irradiating a high-intensity laser pulse on a miniature plasma device consisting of a plasma lens and a plasma mirror. This concept exploits strong spatiotemporal laser-shaping process and high-charge electron acceleration process in the plasma lens, as well as an efficient nonlinear Compton scattering process enabled by the plasma mirror. Our full three-dimensional particle-in-cell simulations demonstrate that in this novel scheme, brilliant gamma-rays with very high conversion efficiency (higher than 10(-2)) and spectral intensity (similar to 10(9) photons/0.1%BW) can be achieved by employing currently available petawatt-class lasers with intensity of 10(21) W cm(-2). Such efficient and intense gamma-ray sources would find applications in wide-ranging areas. ©2019 The Author(s)
Accurate diagnosis of Helicobacter pylori infection by stool antigen test and six other currently available tests in children.
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Long-term efficacy of recombinant hepatitis B vaccine and risk of natural infection in infants born to mothers with hepatitis B e antigen mothers.
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