No abstract

Lifetimes of metastable levels in the ground term of Fe ions within the 3s 2 3p k , kϭ1-5, isoelectronic sequences have been measured. These measurements were performed utilizing ions that were selected by mass to charge ratio while transported from an electron cyclotron resonance ion source to a Kingdon ion trap, where they were captured and then confined for periods of up to 2.1 s. During this storage period, selected emission wavelengths of transitions from metastable levels in the visible or near-ultraviolet spectral regions were isolated using interference filters, and the time-dependent fluorescence intensities were measured using a photomultiplier tube. Measurement precisions on the order of 2% were achieved in favorable cases. The measured lifetimes are ͑Fe X, 3s 2 p 5 2 P 1/2)ϭ13.64Ϯ0.25 ms, ͑Fe XI, 3s 2 3p 4 1 D 2)ϭ9.86Ϯ0.22 ms, ͑Fe XII, 3s 2 3p 3 2 P 3/2)ϭ1.85Ϯ0.24 ms, ͑Fe XII, 3s 2 3p 3 2 P 1/2)ϭ4.38Ϯ0.42 ms, ͑Fe XII, 3s 2 3p 3 2 D 3/2)ϭ20.35 Ϯ1.24 ms, ͑Fe XIII, 3s 2 3p 2 1 D 2)ϭ6.93Ϯ0.18 ms, and ͑Fe XIV, 3s 2 3p 2 P 3/2)ϭ17.52Ϯ0.29 ms. These results are compared with existing and with new theoretical calculations, which have estimated uncertainties on the order of 10-25 %.

Forbidden transitions from levels with 3P and 1D cores in excited configurations of Cl-like Mn IX and Fe X have been isolated using interference filters. The fluorescence decay lifetimes of ions orbiting in a Kingdon ion trap were measured. New relativistic configuration interaction calculations of relevant level lifetimes, to aid the analysis, based on B-spline basis sets, are also presented. Line identifications and experimental lifetimes are Mn IX ((4)D(7/2)-(4)F(9/2)):363(-3/+7) nm; tau(Mn IX3p(4)(3P)3d (4)F(9/2)) = 210+/-42 ms; tau(Fe X,3p(4)(3P)3d (4)F(9/2)) = 85.7+/-9.2 ms; tau(Fe X,3p(4)(3P)3d (4)F(7/2)) = 93+/-30 ms; and tau(Fe X, 3p(4)(1D)3d (2)G(9/2)) = 17.8+/-3.1 ms.

No abstract

Despite widespread mass rollout programs, the rapid spread of the SARS-CoV-2 Omicron variant called into question the effectiveness of the existing vaccines against infection, hospitalization, severity, and mortality compared to previous variants. This systematic review summarizes and compares the effectiveness of the COVID-19 vaccines, with respect to the above outcomes in adults, children, and adolescents. A comprehensive literature search was undertaken on several databases. Only 51 studies met our inclusion criteria, revealing that the protection from primary vaccination against Omicron infection is inferior to protection against Delta and Alpha infections and wanes faster over time. However, mRNA vaccine boosters were reported to reestablish effectiveness, although to a lower extent against Omicron. Nonetheless, primary vaccination was shown to preserve strong protection against Omicron-associated hospitalization, severity, and death, even months after last dose. However, boosters provide more robust and longer-lasting protection against hospitalizations due to Omicron as compared to only primary series.